Built-in cycloid speed reducer of humanoid robot joint pin type output structure and joint module

Abstract

The invention discloses a built-in cycloid speed reducer of a humanoid robot joint pin type output structure and a joint module. The problems that an existing robot joint module is large in size, complex in structure, insufficient in transmission reliability and bearing capacity and the like are solved. According to the invention, the frameless torque motor and the cycloidal-pin wheel speed reducer are designed in an integrated built-in manner, so that the structure is highly compact; an output mechanism of the cycloidal speed reducer adopts a pin type output structure, a plurality of transmission pin shafts arranged on an output flange are directly meshed with pin holes in a cycloidal gear, planetary motion of the cycloidal gear is accurately converted into pure rotation motion of the output flange, and the pin type output structure has the advantages of being simple in structure, reliable in transmission and high in bearing capacity. In addition, a parabola modification method is adopted for the tooth profile of the cycloidal gear, the meshing characteristic of the gear is optimized, the transmission stability is improved, and noise is reduced. The joint module has the advantages of being high in integration degree, high in torque density, high in rigidity, high in impact resistance and the like, and is particularly suitable for humanoid robot joints with strict requirements for space and performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of core components of robots, and in particular relates to a joint module with an integrated motor and reducer. Specifically, it is a joint module applied to the joints of humanoid robots, which adopts a built-in cycloid pinwheel reducer and uses a pin as an output mechanism. Background Art

[0002] Humanoid robots, the crown jewel of robotics technology, place extremely high demands on core components. The performance of the joint module, the robot's "moving joint," directly determines the robot's motion accuracy, load capacity, and dynamic response speed. Currently, the mainstream robot joint reducers are mainly harmonic reducers and RV reducers.

[0003] Due to the elastic deformation transmission principle of the flexible wheel, the harmonic reducer has the inherent defects of low torsional stiffness and limited load-bearing capacity, which makes it difficult to meet the use requirements of humanoid robots in large load and high impact situations (such as somersaults, running and jumping).

[0004] While RV reducers (cycloidal pinwheel planetary transmissions) offer the advantages of high rigidity and load-bearing capacity, their traditional structure typically consists of a planetary gear reduction stage and a cycloidal pinwheel reduction stage. This complex structure and numerous parts result in a large size, weight, and high cost. For humanoid robots striving for extreme lightweight and compactness, the size and weight of traditional RV reducers present a bottleneck in their application.

[0005] Furthermore, in cycloid pinwheel transmissions, the theoretical tooth profile of the cycloid gear must be modified to ensure smooth meshing of multiple teeth, reduce impact and noise, and facilitate lubrication and assembly. While traditional tooth profile modification methods (such as equidistant shifting) can be effective, there is still room for improvement in optimizing transmission errors, increasing meshing rigidity, and enhancing transmission smoothness.

[0006] At the same time, how to more efficiently integrate the reducer and drive motor, further reduce the axial and radial dimensions of the joint module, and adopt a more optimized output structure to improve transmission rigidity and accuracy are key challenges in the current development of humanoid robot joint technology. Summary of the Invention

[0007] The present invention aims to overcome the shortcomings of existing technologies by providing a novel, highly integrated, and high-performance humanoid robot joint pin-type output structure with a built-in cycloid reducer and joint module. This module is designed to achieve the goals of small size, light weight, high rigidity, high torque, high precision, and long life.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] A humanoid robot joint with a pin-type output structure and a built-in cycloid reducer and joint module includes a motor and a cycloid reducer built into the motor, forming an integrated joint module. The cycloid reducer comprises an input crankshaft, a cycloid gear, a pinion housing, and an output mechanism. The input crankshaft drives the cycloid gear to perform planetary motion relative to the pinion housing. The output mechanism converts the cycloid gear's planetary motion into pure rotational motion for output.

[0010] In a preferred embodiment, the motor is an outer rotor frameless torque motor, the stator of which is fixed on the pin-tooth housing of the cycloid reducer, and the rotor directly drives the input crankshaft of the reducer, realizing mechatronics and greatly reducing the axial size of the module.

[0011] The cycloid reducer's output mechanism utilizes a pin-type output structure. This structure comprises an output flange with multiple (usually three or more, evenly distributed) drive pins, and one or more cycloid wheels. Each cycloid wheel has a drive pin hole corresponding to the drive pin. The drive pin passes through the drive pin hole, and the pin hole's diameter is larger than the pin's diameter.

[0012] Its operating principle is as follows: when the input crankshaft drives the cycloid gear in planetary motion, it orbits around the center of the crankshaft while rotating around its own geometric center. Because the diameter of the drive pin hole is larger than the diameter of the drive pin shaft, this gap allows for the cycloid gear's eccentric orbital motion. Simultaneously, the cycloid gear's rotation drives the inner wall of the drive pin hole, shifting the drive pin shaft. Since the drive pin shaft is fixed to the output flange, it forces the output flange to generate pure rotational motion in the same direction and at a speed proportional to the cycloid gear's rotation, thereby achieving motion conversion and deceleration. To improve efficiency and lifespan, a wear-resistant bushing or needle roller bearing can be installed in the pin hole.

[0013] To further optimize transmission performance, the cycloid gear tooth profile of this invention utilizes a parabolic modification method. This method dynamically adjusts the tooth profile modification based on the meshing point position, bringing the tooth profile closer to the theoretical tooth profile in the primary load-bearing area to ensure high stiffness and precision. A smooth transition is achieved in the areas entering and exiting meshing, facilitating the formation of a lubricating oil film, reducing shock and vibration, and resulting in smoother transmission and lower noise.

[0014] The expression of the parabola shaping amount ΔL of the present invention is:

[0015] ΔL=a c (PK-PK0) n +b

[0016] Where PK is the distance between the meshing point and the node on the cycloid gear tooth profile at different meshing phase angles, PK0 is the distance between the meshing point and the node P at the initial reference point, a cis the parabola modification coefficient, n is the parabola modification order, usually n is an even number, and b is the constant term modification coefficient.

[0017] By superimposing the modification amount ΔL along the normal direction onto the theoretical cycloid gear tooth profile equation, the cycloid gear tooth profile equation can be obtained as follows:

[0018]

[0019] Among them, R p is the radius of the pinwheel, (R rp is the radius of the needle tooth, a is the eccentricity, is the pinwheel angle, i H is the transmission ratio of the cycloid pinwheel pair in the conversion mechanism, i H =z p / z c , z p is the number of pinwheel teeth, z c is the number of cycloid gear teeth, K1=az p / R p .

[0020] The built-in cycloid reducer and joint module of the humanoid robot joint pin output structure provided by the present invention have the following beneficial effects:

[0021] 1. Highly integrated and compact structure: The frameless motor is built into the reducer, eliminating the housing, bearings and flanges of the traditional motor, making the axial size of the entire joint module extremely small, light weight and high power density.

[0022] 2. Simple structure and reliable transmission: Compared with other output mechanisms, the pin-type output structure has fewer parts, no complicated intermediate transmission parts, and a direct force flow transmission path, so the structure is simple.

[0023] Simple, easy to assemble and high transmission reliability.

[0024] 3. Strong load-bearing capacity and high rigidity: The pin-type output transmits torque simultaneously through multiple pins, which ensures uniform force and strong load-bearing capacity. The output flange is directly supported by a large-diameter cross-roller bearing, providing the joint with extremely high radial, axial and anti-overturning rigidity.

[0025] 4. Smooth operation and low noise: The parabolic modified cycloid gear tooth profile optimizes the meshing characteristics, makes the transmission smoother, and effectively reduces transmission error, vibration and noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the front and oblique side of a humanoid robot joint disc output structure with a built-in cycloid reducer and a joint module according to the present invention;

[0027] Figure 2 This is a schematic diagram of the anticline side product of a humanoid robot joint disc output structure with a built-in cycloid reducer and a joint module according to the present invention;

[0028] Figure 3 This is an exploded schematic diagram of the built-in cycloid reducer and joint module of the humanoid robot joint disc output structure described in the present invention, showing the assembly relationship of the main components;

[0029] Figure 4 This is an axial cross-sectional view of the built-in cycloid reducer and joint module of the humanoid robot joint disc output structure described in the present invention, clearly showing the internal structure;

[0030] Figure 5 This is a schematic diagram of the principle of the pin-type output mechanism of the present invention, showing the coordination and kinematic relationship between the cycloid wheel, the transmission pin shaft, and the output flange;

[0031] Figure 6 Schematic diagram of the cycloid gear tooth profile using parabolic modification in the present invention.

[0032] The reference numerals in the figure are: 1-joint module housing, 2-output flange, 3-crankshaft support bearing, 4-output flange support bearing, 5-pin, 6-swing arm bearing, 7-cycloid wheel, 8-pin gear housing, 9-pin gear, 10-input crankshaft, 11-motor stator, 12-motor rotor, 13-input support end, 14-motor driver and end cover assembly, 701-transmission pin hole. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The following examples are used to illustrate the present application but are not intended to limit the scope of the present application. Similarly, the following examples are only some embodiments of the present application and not all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of this application.

[0034] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the quantity of the technical features indicated. Thus, features defined as "first" or "second" may explicitly or implicitly include at least one of these features.

[0036] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0037] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0038] In response to the above problems, the present application makes improvements and innovations and proposes the following embodiments.

[0039] In one embodiment, see Figures 1 to 3 The present invention provides a built-in cycloid reducer and joint module of a humanoid robot joint pin-type output structure. The module deeply integrates the motor and the reducer in structure to form a compact whole. The cycloid reducer includes an input crankshaft (10), two cycloid wheels (7), a pin-tooth housing (8) and a pin-type output mechanism (5); the input crankshaft (10) drives the cycloid wheels (7) to perform planetary motion relative to the pin-tooth housing (8); the output mechanism (5) is used to convert the planetary motion of the cycloid wheels (7) into pure rotational motion and output it.

[0040] The motor part adopts a frameless torque motor, including an annular stator (11) and a cup-shaped rotor (12). The stator (11) is tightly mounted on the outer circumference of the pin-tooth housing (8) of the cycloid reducer by means of interference fit or screw fixation. The center of the cup bottom of the rotor (12) is rigidly connected to the input end of the input crankshaft (10), the input component of the cycloid reducer, by splines or bolts.

[0041] In some embodiments, see Figure 3 、 Figure 4 、 Figure 5 The input crankshaft (10) is a double eccentric structure, with the two eccentric parts having a phase difference of 180 degrees to balance the radial exciting force. The two cycloid wheels (7) are respectively mounted on the two eccentric parts through the swing arm bearings (6).

[0042] In some embodiments, see Figure 3 、 Figure 4 、 Figure 5 The pin gear housing (5) is an annular part, and a circle of pin teeth (9) as an external meshing pin wheel are uniformly distributed on its inner wall. The short-width epicycloid tooth profile of the cycloid wheel (7) meshes with these pin teeth to form a planetary reduction mechanism with a tooth number difference of 1.

[0043] The core output mechanism of the present invention is the pin-type output structure. Figure 5 As shown, it consists of a plurality of transmission pins (5) fixed to the output flange (2) and transmission pin holes (701) opened on the cycloid wheel (7). The transmission pins (5) are perpendicular to the output flange surface and are evenly distributed. The cycloid wheel (7) is provided with transmission pin holes (701) corresponding in number and position. The diameter of these pin holes is larger than the diameter of the pins by a certain value (approximately twice the eccentricity) to accommodate the revolution of the cycloid wheel.

[0044] When the motor rotor (12) drives the input crankshaft (10) to rotate, the cycloid wheel (7) performs planetary motion under the constraints of the pin teeth. Its motion can be decomposed into rotation around its own center and revolution around the center of the crankshaft. The revolution of the cycloid wheel (7) is manifested as the entire wheel body swinging in the gap between the transmission pin hole (701) and the transmission pin shaft (5), without transmitting motion. The rotation of the cycloid wheel (7) causes the inner wall of the pin hole (701) to push the transmission pin shaft (5) to rotate. Since all the transmission pin shafts (5) are fixed to the output flange (2), the entire output flange (3) is driven, generating a pure rotation output.

[0045] The output flange (2) serves as the power output end of the entire joint, and its outer edge is mounted on a large-diameter thin-walled cross roller bearing (4). The inner ring of the bearing is fixed to the pin gear housing (8), and the outer ring is fixed to the output flange (2). The cross roller bearing (4) can simultaneously withstand radial force, axial force and overturning moment, providing strong support stiffness for the joint.

[0046] In the tooth profile design, Figure 6 As shown, the tooth profile of the cycloid wheel (7) is not a standard short-amplitude epicycloid, but adopts an advanced parabolic shaping method. The parabolic shaping amount ΔL changes with the distance between the meshing point and the node on the cycloid wheel tooth profile, so that the tooth profile is as close to the theoretical tooth profile as possible in the main working section. This shaping method ensures that during the transmission process, multiple gear teeth can smoothly enter and exit the meshing, avoiding impact and interference, while optimizing the stress distribution in the contact area, improving the transmission accuracy, efficiency and service life of the reducer.

[0047] In summary, the present invention achieves significant improvements in the compactness, reliability, rigidity and operational smoothness of the humanoid robot joint module through mechatronic design, combined with a simple and reliable pin-type output mechanism and advanced tooth profile modification technology.

[0048] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A humanoid robot joint pin-type output structure with a built-in cycloid reducer and a joint module, comprising a motor and a cycloid reducer built into the motor, the two forming an integrated joint module; the cycloid reducer comprises an input crankshaft (10), a cycloid wheel (7), a pin-tooth housing (8) and an output mechanism (5); the input crankshaft (10) drives the cycloid wheel (7) to perform planetary motion relative to the pin-tooth housing (8); the output mechanism (5) is used to convert the planetary motion of the cycloid wheel (7) into pure rotational motion and output it, characterized in that The output mechanism is a pin-type output structure.

2. The built-in cycloid reducer and joint module of the humanoid robot joint pin-type output structure according to claim 1, characterized in that: The motor is a frameless torque motor, the stator (11) of which is fixed to the outside of the pin-tooth housing (8), and the rotor (12) of which is fixed to the input crankshaft (10).

3. The built-in cycloid reducer and joint module of the humanoid robot joint pin-type output structure according to claim 1, characterized in that: The pin-type output structure comprises an output flange (2) and at least three transmission pins (5) uniformly distributed on the output flange (2); the cycloid wheel (7) is provided with transmission pin holes (701) corresponding to the number and distribution positions of the transmission pins (5); each of the transmission pins (5) passes through the corresponding transmission pin hole (701), thereby transmitting the rotational motion of the cycloid wheel (7) to the output flange (2).

4. The built-in cycloid reducer and joint module of the humanoid robot joint pin-type output structure according to claim 3, characterized in that: The diameter of the transmission pin hole (701) is larger than the diameter of the transmission pin shaft (5) to allow the orbital motion of the cycloid wheel (7).

5. The built-in cycloid reducer and joint module of the humanoid robot joint pin-type output structure according to claim 3, characterized in that: A bushing or a needle roller bearing is provided on the inner wall of the transmission pin hole (701), and the transmission pin shaft (5) cooperates with the bushing or the needle roller bearing to form a sliding or rolling friction pair.

6. The built-in cycloid reducer and joint module of the humanoid robot joint pin-type output structure according to claim 1, characterized in that: The cycloid reducer is a double cycloid wheel structure, comprising two cycloid wheels (7) arranged symmetrically with a phase difference of 180 degrees. The input crankshaft (10) is a double eccentric structure, and the two cycloid wheels (7) are respectively mounted on the two eccentric parts of the input crankshaft (10) through swing arm bearings (6).

7. The built-in cycloid reducer and joint module of the humanoid robot joint pin-type output structure according to claim 1, characterized in that: The output flange (2) is rotatably connected to the pin gear housing (8) via a cross roller bearing (5), and the cross roller bearing (5) simultaneously bears radial force, axial force and overturning moment.

8. The built-in cycloid reducer and joint module of the humanoid robot joint pin-type output structure according to claim 1, characterized in that: The tooth profile of the cycloid wheel (7) adopts a parabolic shaping method.

9. The built-in cycloid reducer and joint module of the humanoid robot joint pin-type output structure according to claim 8, characterized in that: The expression of the parabola modification amount ΔL is: ΔL=a c (PK-PK0) n +b Where PK is the distance between the meshing point and the node on the cycloid gear tooth profile at different meshing phase angles, PK0 is the distance between the cycloid gear meshing point and the node P at the initial reference point, a c is the parabola modification coefficient, n is the parabola modification order, and b is the constant term modification coefficient.

10. The built-in cycloid reducer and joint module of the humanoid robot joint pin-type output structure according to claim 8, characterized in that: The tooth profile equation of the cycloid wheel (8) is: Among them, R p is the radius of the pinwheel, (R rp is the radius of the needle tooth, a is the eccentricity, is the pinwheel angle, i H is the transmission ratio of the cycloid pinwheel pair in the conversion mechanism, i H =z p / z c , z p is the number of pinwheel teeth, z c is the number of cycloid gear teeth, K1=az p / R p .

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