High-torque lightweight joint motor assembly

Abstract

The utility model discloses a high torsion lightweight joint motor assembly adopts modularization design, and mainly includes frameless torque motor assembly, planetary reducer assembly, drive controller, double encoder system, casing, the planetary reducer assembly is placed in the left side and inner chamber of frameless torque motor assembly, and double encoder system is in the cavity center, and drive controller is placed in the right side of frameless torque motor assembly, and casing is placed in the outside of planetary reducer assembly and plays the sealing effect, the utility model discloses through the integration design, will high torque density frameless torque motor module, single -stage big transmission ratio planetary reducer, high bandwidth drive controller, double encoder system and lightweight high -strength casing and end cap integration in one. Each component is through accurate mechanical and electrical connection, forms a high -efficient, compact transmission system. Satisfy heavy -duty robot or big load robot dog high quality torque density demand.

Description

Technical Field

[0001] This utility model belongs to the field of articulated motors, specifically relating to a high-torque, lightweight articulated motor assembly for use in robotics, automated equipment, and aerospace. Background Technology

[0002] In fields such as robotics, automation equipment, and aerospace, articulated motor assemblies are key components for achieving high-precision motion control. Traditional articulated motor assemblies typically consist of a motor, reducer, controller, encoder, and other components integrated together through complex mechanical and electrical connections to form a complete transmission system. However, traditional designs have many limitations and struggle to meet the demands of modern applications for high precision, high load capacity, and compact space.

[0003] The typical structure of a traditional articulated motor assembly includes a motor, reducer, controller, encoder, and other main components. Traditional articulated motor assemblies typically employ a split design, with each component integrated via mechanical connections such as bolts and couplings. The motor serves as the power source, and the reducer lowers the speed and increases the torque, ultimately transmitting power to the articulated ends. The controller and encoder are used to achieve precise position and speed control.

[0004] The main defects are as follows:

[0005] (1) Traditional articulated motor assemblies adopt a split design, with each component installed independently, resulting in a large overall size that is difficult to meet the requirements of compact space. At the same time, traditional motors have low torque density and cannot provide high torque output in small sizes. (2) The transmission ratio of traditional single-stage planetary reducers is usually limited to a maximum of 8, making it difficult to achieve a higher transmission ratio. Using two-stage reduction can increase the transmission ratio, but the size, weight, and types of components will increase significantly, failing to meet the application requirements of high compactness, high load, and high precision. (3) Traditional motor control systems use a single encoder feedback, which has limited accuracy and cannot achieve multi-turn memory function. The controller's protection function is insufficient, making it prone to failure under complex working conditions. (4) Traditional motor housings and end covers are made of ordinary aluminum alloy or steel, which are heavy and lack strength. Traditional manufacturing processes cannot achieve high-precision gear machining and housing forming, limiting the overall performance of the motor. Utility Model Content

[0006] This utility model provides a high-torque, lightweight joint motor assembly. The technical problem to be solved is that the joint motor assembly of heavy robots has problems such as large size, low torque density, limited transmission ratio, and insufficient control precision, which meet the application requirements of heavy robots, robot dogs and other applications with high precision, high load and compact space.

[0007] To solve the above technical problems, this utility model provides a high-torque lightweight joint motor assembly, characterized in that: it includes a frameless torque motor assembly (1), a planetary reducer assembly (2), a drive controller (3), a dual encoder system (4), and a housing (5); the planetary reducer assembly (2) is placed on the left side and inside the frameless torque motor assembly (1), the dual encoder system (4) is placed at the center of the inside, the drive controller (3) is placed on the right side of the frameless torque motor assembly (1), and the housing (5) is placed outside the planetary reducer assembly (2) for sealing.

[0008] Furthermore, the frameless torque motor assembly (1) adopts a brushless DC motor.

[0009] Furthermore, the frameless torque motor assembly (1) includes a motor housing (6), a stator (9), a rotor (10), a shaft (11), and a retaining ring (15); the stator (9) is interference-fitted with the motor housing (6), an air gap is formed between the rotor (10) and the stator (9), the rotor (10) is fixedly connected to the shaft (11), and is axially positioned by the end retaining ring (15), the motor housing (6) is fixed with a right end cover (7) and a left end cover (8) respectively, and the shaft (10) is supported on the left end cover (8) and the gear ring (21) of the planetary reducer assembly (2).

[0010] Furthermore, the air gap between the rotor (10) and the stator (9) is (0) (7) mm.

[0011] Furthermore, the right end cover (7) and the left end cover (8) of the motor both adopt a double stop structure, and the right end cover (7), the left end cover (8), and the motor housing (6) are all made of integrated magnesium alloy extrusion molding; the rotating shaft (10) is integrated with the sun gear (15) in the planetary reducer assembly (2).

[0012] Furthermore, the inner ring of the rotating shaft (10) is provided with (2) grooves, the inner hole of the groove is treated with tungsten carbide, and a sealing ring (12) and a roller (13) are provided therein. The inner ring of the bearing (14) is connected to the inner hole of the groove of the rotating shaft (10), and the outer ring is connected to the left end cover (8) of the motor. The sealing ring (12) is made of oil-lubricated microcapsule material.

[0013] Furthermore, the planetary reducer assembly is a large transmission ratio NW type planetary gear set structure.

[0014] Furthermore, the planetary reducer assembly (2) includes a sun gear (16), planet gears (17), a frame (18), a planet gear shaft (19), and a gear ring (21). The sun gear (16) has a short shaft structure at both ends, with one end integrated with the rotating shaft (10) and the other end rotatably connected to the frame (18). The planet gear (17) is a double planet gear, with the large diameter tooth of the double gear designed as a helical cylindrical tooth and placed on the left side, and the small diameter tooth designed as a spur cylindrical gear and placed on the right side. The small diameter tooth meshes with the gear ring (21) and is placed in the cavity of the motor (1). The outer circle of the gear ring (21) is fixedly connected to the left end cover (8) of the motor. The toothed part of the inner hole of the gear ring (21) is placed on the left end, and the right end is rotatably connected to the frame. The planet gear shaft (19) is mounted on the frame (18), and the planet gears (17) are rotatably connected to the planet gear shaft (19).

[0015] Furthermore, the frame (18) adopts an integral structure cast from thin-walled titanium alloy. The left side is a closed sidewall, and the inner hole in the middle of the sidewall is connected to the sun gear through a small bearing (24). The right side is an L-shaped annular groove structure, and its outer circle is connected to the gear ring through a large bearing (23).

[0016] Furthermore, the planetary gear (17) meshes with the sun gear (16) and the ring gear (21), respectively.

[0017] Beneficial Effects: This utility model is a highly reliable, high-torque, lightweight joint motor assembly based on planetary gear reducers. Through integrated design, it integrates a high-torque-density frameless torque motor module, a single-stage large-ratio planetary reducer, a high-bandwidth drive controller, a dual-encoder system, and a lightweight, high-strength housing and end caps into one unit. The components are connected by precise mechanical and electrical connections, forming a highly efficient and compact transmission system. This meets the high-quality torque density requirements of heavy-duty robots or high-load-bearing robotic dogs. Attached Figure Description

[0018] Figure 1 3D layout diagram of the joint motor assembly

[0019] Figure 2 A two-dimensional half-section diagram of the joint motor assembly.

[0020] Figure 3 A schematic diagram of the three-dimensional cross-section of the frame.

[0021] Figure 4 This is a three-dimensional schematic diagram of the drive controller and encoder assembly placed in the motor. Detailed Implementation

[0022] To make the purpose, content and advantages of this utility model clearer, the specific embodiments of this utility model will be described in further detail below.

[0023] like Figure 1As shown, the present invention proposes a high-torque lightweight joint motor assembly, which adopts a modular design and mainly includes a frameless torque motor assembly 1, a planetary reducer assembly 2, a drive controller 3, a dual encoder system 4, and a housing 5.

[0024] The planetary reducer assembly 2 is located on the left side and inside the frameless torque motor assembly 1. The dual encoder system 4 is located at the center of the inner cavity. The drive controller 3 is located on the right side of the frameless torque motor assembly 1. The housing 5 is located outside the planetary reducer assembly 2 for sealing. It features high-density torque, 17-bit dual encoders, high-bandwidth drive control (constant speed control from 0-0.9 Nmax), and an IP67 protection rating.

[0025] like Figure 2 As shown, the frameless torque motor assembly 1 adopts a brushless DC motor design and mainly includes a motor housing 6, a right end cover 7, a left end cover 8, a stator 9, a rotor 10, a shaft 11, a sealing ring 12, a roller 13, a bearing 14, and a retaining ring 15.

[0026] The stator 9 is fixedly connected to the motor housing 6 by an interference fit. The air gap between the rotor 10 and the stator 9 is 0.7mm. The rotor 10 is fixedly connected to the shaft 11 by a radial fit and is axially positioned by the end retaining ring 15. The right end cover 7 and the left end cover 8 of the motor both adopt a double stop structure and are fixed to both ends of the motor housing 6 for precise positioning. In order to meet the requirements of lightweighting and considering the rigidity and strength, the right end cover 7, the left end cover 8, and the motor housing 6 are all made of integrated magnesium alloy extrusion molding. They are all fitted to the motor housing 6 by a radial clearance fit of stop H7 / g6, and the end face contacts are fixedly connected by bolts.

[0027] The rotating shaft 10 adopts a titanium alloy thin-walled curved groove structure and is integrated with the steel sun gear 15 in the planetary reducer assembly 2. The inner ring of the rotating shaft 10 has two grooves, and the inner hole of the groove is treated with tungsten carbide, which contains a sealing ring 12 and a roller 13. The inner ring of the bearing 14 is connected to the inner hole of the groove of the rotating shaft 10, and the outer ring is connected to the left end cover 8 of the motor. The roller 13 is connected to the inner hole of the rotating shaft 10 and the outer circle of the gear ring 21, supporting the rotating shaft 10 on the left end cover 8 of the motor and the gear ring 21 of the planetary reducer assembly 2.

[0028] The sealing ring 12 is made of oil-lubricated microcapsule material, which has a low coefficient of friction and reduces heat generation. The roller 13 is a set of ceramic rollers with a diameter of 1-1.5 mm; the bearing 14 is a self-lubricating and sealing double-row angular contact ball bearing, which can withstand axial, radial and overturning moments, while satisfying its own lubrication and sealing requirements.

[0029] like Figure 2As shown, the planetary reducer assembly 2 is an NW type planetary gear structure with a large transmission ratio of 20-23, precision machining process, and backlash not greater than 20 arcmin. It mainly includes a sun gear 16, planet gears 17, frame 18, planet gear shaft 19, anti-friction pad 20, gear ring 21, needle roller bearing 22, large bearing 23, small bearing 24, oil seal 25, retaining ring 26, and bolt 27.

[0030] The sun gear 16 has a short shaft structure at both ends. One end is integrated with the rotating shaft 10, connected radially by a flange key and axially by a locating pin. The other end is connected to the inner ring of the small bearing 24 with an overfit, and rotates relative to the frame 18. The sun gear 16 has a hollow design with a hole diameter of not less than 8mm to meet the requirements of wiring and sensors. The hollow part in this application is used for sensor placement, but is not limited to this purpose.

[0031] Planetary gear 17 is a double planetary gear. The large-diameter tooth of the double-gear is designed as a helical cylindrical tooth and is located on the left side; the small-diameter tooth is designed as a spur cylindrical gear and is located on the right side. The small-diameter tooth meshes with the gear ring 21 and is located in the cavity of motor 1. This achieves high load-bearing capacity in a small volume, easy processing, and low cost.

[0032] The gear ring 21 is an annular structure with a flange. Its outer circle is fitted with the left end cover 8 of the motor through a stop clearance, and the flange end is fixedly connected to the left end cover 8 of the motor by bolts 27. The toothed part of the inner hole of the gear ring 21 is located at the left end, and the right end is a smooth hole that fits with the outer ring of the large bearing 23.

[0033] The sun gear 16, planet gear 17, and gear ring 21 all use a module of 0.8 to 0.85, a pressure angle of 22.5°, a tooth tip height coefficient of 0.9, a precision of grade 5, and are made of 20Cr2Ni4A material. They undergo micro-carburizing and quenching treatment, with the carbon layer depth controlled at 0.12-0.15, and are shot peened with microparticles to achieve both surface hardness and core toughness in the teeth, meeting the requirements of high speed and heavy load.

[0034] The frame 18 adopts a thin-walled titanium alloy cast integral structure. The left side is a closed sidewall, with the inner hole in the middle of the sidewall transitionally connected to the small bearing 24. The right side has an L-shaped annular groove structure, the outer circle of which is connected to the inner ring of the large bearing 23 and axially fixed to the frame 18 by a retaining ring 26. An oil seal 25 is provided in its inner hole, which is connected to the rotating shaft 10 for sealing. The frame 18 is provided with planetary gear shaft hole 28, bearing seat hole 29, oil seal seat hole 30 and reinforcing rib 31, and has been anodized. The part in contact with the friction-reducing pad 20 is locally treated with tungsten carbide.

[0035] One end of the planetary gear shaft 19 is radially clearance-fitted with the planetary gear shaft hole 28 of the frame 18, and its end face is in contact with the end face of the planetary gear shaft hole 28. The other end is radially transition-fitted with the planetary gear shaft hole 28 of the frame 18. The planetary gear 17 is supported on the planetary gear shaft 19 by needle roller bearings 22.

[0036] In the planetary reducer assembly 2, planetary gears 17 mesh with sun gear 16 and ring gear 21 respectively.

[0037] The friction-reducing pad 20 is made of polyetheretherketone (PEEK).

[0038] Large bearing 23 and small bearing 24 are self-lubricating, sealed angular contact thrust ball bearings. The sealing ring 26 is made of oil-lubricated microcapsule material, which has a low coefficient of friction and low energy consumption.

[0039] The housing 5 is an end cap structure, manufactured using a magnesium-aluminum alloy extrusion molding process. It has an internal groove to house a sealing ring 32, separating the assembly from the external medium. The inner hole of the housing 5 is radially connected to the left end cap 8 of the motor, and the end is fixedly connected to the left end cap 8 of the motor and the end face of the motor housing 6 by bolts through an oil-resistant asbestos rubber gasket 15.

[0040] The bearings 14 and rollers 13 in the frameless torque motor assembly 1, the large bearing 23 and small bearing 24 in the planetary reducer assembly 2, the sealing ring 12 in the frameless torque motor assembly 1, the sealing ring 26 in the planetary reducer assembly 2, and the sealing ring 32 in the housing 5 form a closed-loop sealing structure with load-bearing, stacked support structure and low friction, enabling the assembly to withstand axial, radial, and overturning moment loads, while also achieving an IP67 protection rating for the assembly.

[0041] The housing 5, motor housing 6, left end cover 7, and right end cover 8 are all made of Mg-3.33Sm-0.55Zn-0.46Zr material in the T6 temper, with a tensile strength of 340MPa, a yield strength of 347MPa, an elongation of 12.1%, and a density of 1.85-1.88g / cm³. 3 .

[0042] The drive controller 3 includes a drive control board assembly 33, a cover 34, and an O-ring 35. The drive control board assembly 33 is fixedly connected to the right end cover 8. The cover 34 and the right end cover 8 are radially sealed together by the stop of the O-ring 35. The cover 34 and the end face of the right end cover 8 are fixedly connected by bolts 36. The cover 34 is made of thin-walled resin. The drive controller 3 has multiple control modes, including width speed control and precise position control, which can be flexibly adjusted according to actual needs. The controller 3 has over-temperature, over-voltage, and overload protection functions to ensure stable operation of the motor under complex working conditions. The controller 3 is connected to the dual encoder system 4 through a high-speed communication interface (CAN bus or EtherCAT) to read position and speed data in real time and perform precise control according to a preset control algorithm.

[0043] The dual encoder system 4 comprises a small code disk assembly 37 and a large code disk assembly 38. Its sensors are positioned corresponding to those on the drive control board assembly 33. The left end of the small code disk assembly 37 is fixedly connected to the frame 18 via precision threads. The left end of the large code disk assembly 38 is fixedly connected to the rotating shaft 10 via precision threads. This system provides real-time feedback of the output position information, eliminating the need for continuous power-on multi-turn memory and improving product reliability and accuracy.

[0044] Working principle:

[0045] After receiving the command, the drive controller 3 inside the joint motor assembly 1 reads the position, speed and other information of the joint motor assembly 1 provided by the encoder 4. The drive current output by the driver 3 flows through the stator winding 9 of the motor 1, generating a rotational magnetic field that interacts with the permanent magnet on the rotor 10 of the motor 1, generating an electromagnetic torque that drives the rotor 10 to rotate. The sun gear 16 of the planetary reducer assembly 2 is connected to the shaft 11 of the motor rotor 10, inputting the electromagnetic torque into the reducer assembly 2. Its speed reduction and torque amplification effect meets the low-speed and high-torque requirements of the joint motor assembly 1.

[0046] The magnetic dual encoder 4 is directly mounted on the shaft 11 of the motor 1 and the output frame 18 of the reducer 2, and feeds back the position and speed to the drive controller 3 in real time, forming a closed-loop controller.

[0047] Key points of this utility model

[0048] 1. Features high-quality torque density, 17-bit dual encoders, high-bandwidth drive controller (speed control from 0 to 0.9nmax), and IP67 protection rating.

[0049] 2. The frameless torque motor assembly adopts a brushless DC motor design. Its shaft is integrated with the steel sun gear in the planetary reducer assembly using a titanium alloy thin-walled curved groove structure. It is connected radially via a flange-type key and axially fixed by a locating pin. The left end of the shaft has two grooves in its curved groove inner hole, with the inner hole treated with tungsten carbide. The sealing rings inside are made of oil-lubricated microcapsules to reduce wear and energy consumption. The rollers (bearings) inside are a set of ceramic rollers with a diameter of 1-1.5 mm. The right end of the shaft has a self-lubricating, self-sealing bearing in its curved groove inner hole to withstand axial, radial, and overturning moments, providing stable support for the motor shaft. This, together with the frame support bearing, forms a superimposed support, satisfying the requirements for axial force, radial force, and overturning moment, while also meeting the needs of compact space arrangement and lightweight design.

[0050] 3. The planetary reducer assembly is an NW-type planetary gear set structure with a large transmission ratio of 20-23 and a backlash of no more than 20 arcmin. The sun gear features a hollow design with a bore diameter of no less than 8mm to meet wiring and sensor requirements. The planet gears are double-linked planetary gears; the large-diameter teeth are helical cylindrical teeth located on the left, while the small-diameter teeth are spur cylindrical gears located on the right. The small-diameter teeth mesh with the gear ring within the motor cavity. This achieves high load capacity in a small volume, easy processing, and low cost. The sun gear, planet gears, and gear ring in the assembly all use 20Cr2Ni4A material with a module of 0.8-0.85, a pressure angle of 22.5°, a tooth tip height coefficient of 0.9, and a precision of grade 5. They undergo micro-carburizing and quenching treatment, with the carbon layer depth controlled at 0.12-0.15mm, and are subjected to micro-particle shot peening to achieve both surface hardness and core toughness in the teeth, meeting the requirements of high speed, heavy load, and high reliability.

[0051] This utility model integrates a high torque density frameless torque motor module, a large transmission ratio planetary reducer, a high-bandwidth drive controller, a dual encoder system, and a lightweight, high-strength housing. It combines lightweight, high-strength, and super-smooth materials with advanced extrusion, casting, and high-precision gear manufacturing processes. The overall layout adopts a space-sharing and overlapping design, and the transmission components use overlapping support to reduce the amount of bearings and size occupation. It features high precision, high load capacity, small size, light weight, and high reliability, solving the demand for high-quality torque density in compact spaces in fields such as heavy-duty robots. It has significant economic benefits and broad application prospects.

[0052] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A high-torque, lightweight joint motor assembly, characterized in that: The assembly includes a frameless torque motor assembly (1), a planetary reducer assembly (2), a drive controller (3), a dual encoder system (4), and a housing (5). The planetary reducer assembly (2) is located on the left side and inside the frameless torque motor assembly (1), the dual encoder system (4) is located at the center of the inner cavity, the drive controller (3) is located on the right side of the frameless torque motor assembly (1), and the housing (5) is located outside the planetary reducer assembly (2) for sealing purposes. The planetary reducer assembly (2) includes a sun gear (16), planet gears (17), a frame (18), planet gear shafts (19), and a gear ring (21). The sun gear (16) consists of two... The short shaft structure is integrated with the rotating shaft (11) at one end and rotatedly connected to the frame (18) at the other end. The planetary gear (17) is a double planetary gear. The large diameter tooth of the double gear is designed as a helical cylindrical tooth and placed on the left side. The small diameter tooth is designed as a spur cylindrical gear and placed on the right side. The small diameter tooth meshes with the gear ring (21) and is placed in the cavity of the frameless torque motor assembly (1). The outer circle of the gear ring (21) is fixedly connected to the left end cover (8) of the motor. The toothed part of the inner hole of the gear ring (21) is placed on the left end and rotatedly connected to the frame at the right end. The planetary gear shaft (19) is installed on the frame (18) and rotatedly connected to the planetary gear shaft (19).

2. The high-torque, lightweight joint motor assembly according to claim 1, characterized in that: The frameless torque motor assembly (1) adopts a brushless DC motor.

3. The high-torque, lightweight joint motor assembly according to claim 1, characterized in that: The frameless torque motor assembly (1) includes a motor housing (6), a stator (9), a rotor (10), a shaft (11), and a retaining ring (15). The stator (9) is interference-fitted with the motor housing (6), and an air gap is formed between the rotor (10) and the stator (9). The rotor (10) is fixedly connected to the shaft (11) and is axially positioned by the end retaining ring (15). The motor housing (6) is fixed with a right end cover (7) and a left end cover (8) at both ends. The shaft (11) is supported on the left end cover (8) and the gear ring (21) of the planetary reducer assembly (2).

4. The high-torque, lightweight joint motor assembly according to claim 2, characterized in that: The air gap between the rotor (10) and the stator (9) is 0.7 mm.

5. A high-torque, lightweight joint motor assembly according to claim 2, characterized in that: The right end cover (7) and the left end cover (8) of the motor both adopt a double stop structure. The right end cover (7), the left end cover (8), and the motor housing (6) are all made of integrated magnesium alloy extrusion molding. The rotating shaft (11) is integrated with the sun gear (16) in the planetary reducer assembly (2).

6. The high-torque, lightweight joint motor assembly according to claim 2, characterized in that: The inner ring of the rotating shaft (11) has two grooves. The inner hole of the groove is treated with tungsten carbide. It is equipped with a sealing ring (12) and a roller (13). The inner ring of the bearing (14) is connected to the inner hole of the groove of the rotating shaft (11), and the outer ring is connected to the left end cover (8) of the motor. The sealing ring (12) is made of oil-lubricated microcapsule material.

7. A high-torque, lightweight joint motor assembly according to any one of claims 1-6, characterized in that: The planetary reducer assembly is a large transmission ratio NW type planetary gear set structure.

8. The high-torque, lightweight joint motor assembly according to claim 1, characterized in that: The frame (18) adopts an integral structure made of thin-walled titanium alloy. The left side is a closed sidewall, and the inner hole in the middle of the sidewall is connected to the sun gear through a small bearing (24). The right side is an L-shaped annular groove structure, and its outer circle is connected to the gear ring through a large bearing (23).

9. A high-torque, lightweight joint motor assembly according to claim 8, characterized in that: The planetary gear (17) meshes with the sun gear (16) and the ring gear (21), respectively.

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