A hollow planetary reducer combined with a frameless torque motor joint module

Abstract

This utility model relates to a joint module combining a hollow planetary reducer and a frameless torque motor, comprising a main housing, a rear housing, a frameless torque motor, and a hollow planetary reducer. The magnetic rotor assembly of the frameless torque motor is directly connected to the sun gear of the reducer, and an axial heat dissipation channel is provided at the center of the reducer. The innovations are: ① a spiral flow guiding structure is set on the inner wall of the axial heat dissipation channel to enhance heat dissipation; ② a gradient composite wear-resistant coating is used on the planetary gear tooth surface to improve service life. Through integrated design, a 40% reduction in temperature rise and an improvement in transmission accuracy to ±0.02°C are achieved, solving the two major technical problems of insufficient heat dissipation and excessive wear in robot joints.

Description

Technical Field

[0001] This utility model belongs to the field of robot joint drive technology, specifically relating to a joint module that combines a hollow planetary reducer with a frameless torque motor, which is suitable for high-precision transmission scenarios such as industrial robots and surgical robotic arms. Background Technology

[0002] The application of existing joint modules in fields such as industrial robots and precision medical equipment faces severe challenges. Their technical bottlenecks mainly lie in two aspects: thermal management failure and deterioration of transmission accuracy, which are analyzed in detail below.

[0003] Thermal management failure issues: The enclosed structure leads to significant heat accumulation problems. Traditional heat dissipation solutions have fundamental contradictions; the integration of water-cooled piping occupies space in the hollow channel, resulting in a 60% reduction in wiring capacity, and cannot meet the requirements of high-frequency switching noise on multi-joint power boards, which severely interferes with control signals.

[0004] Deterioration of transmission accuracy: Wear is the main cause of accuracy degradation in planetary reduction mechanisms. The surface hardness of the carburized steel planetary gears is insufficient, resulting in a pitting rate of 0.15mm under alternating loads. 3 / N·m; After 6000 hours of operation, the pitting area on the tooth surface is >18%, and the transmission backlash increases from the initial 5 arc minutes to >20 arc minutes; resulting in a decrease in repeatability accuracy of >40%. Utility Model Content

[0005] The main purpose of this utility model is to provide a joint module that combines a hollow planetary reducer with a frameless torque motor, which can effectively solve the problems in the background art.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] A joint module combining a hollow planetary reducer and a frameless torque motor includes a main housing, a rear housing, a frameless torque motor, and a hollow planetary reducer.

[0008] The coil of the frameless torque motor is fixed to the inner wall of the main housing, and the magnetic rotor assembly covers the outer side of the coil and is coaxially and directly connected to the sun gear of the hollow planetary reducer.

[0009] The hollow planetary reducer includes an internal gear ring, a sun gear, planet gears and a planet carrier, and has an axial heat dissipation channel in the center, with a spiral flow guiding structure on the inner wall of the channel;

[0010] The planetary gear teeth are coated with a gradient composite wear-resistant coating.

[0011] Furthermore, the pitch of the spiral guide structure is 0.8-1.2 times the channel diameter, the groove depth is 0.3-0.5 mm, and the guide groove is inclined at an angle of 15° to 20° with the rotation direction of the planetary carrier.

[0012] Furthermore, the gradient composite wear-resistant coating comprises three layers: a bonding layer of chromium aluminum nitride material with a thickness of 3-5 μm; a transition layer of chromium aluminum nitride composite tungsten carbide material with a thickness of 8-12 μm; and a working layer of cobalt-doped tungsten carbide material with a thickness of 10-15 μm.

[0013] Furthermore, a cross roller bearing is installed between the planetary carrier and the main housing, and the bearing raceway surface is nitrided to a hardness of not less than 900HV.

[0014] Furthermore, the axial heat dissipation channel forms a composite cavity with both heat dissipation airflow conduction and cable accommodation and organization functions through the spiral flow guiding structure of the inner wall.

[0015] This utility model has the following beneficial effects:

[0016] 1. When the robot joints are under continuous load, the internal temperature can be stably controlled below 45℃, which is nearly half that of traditional joint modules. The key is the design of a spiral guide channel in the central channel - like adding threads to the channel, allowing the cooling airflow to rotate and quickly remove heat. At the same time, the spiral structure of the inner wall of the channel acts like a "sponge" to efficiently absorb heat, greatly enhancing the heat dissipation capacity.

[0017] 2. The planetary gear surface is coated with three layers of special coating: the first layer is an ultra-hard anti-scratch layer; the second layer is a crack-resistant buffer layer; and the third layer is a self-lubricating layer, which can extend the gear life to 25,000 hours, improve accuracy by 4 times, and reduce repeatability error to only ±0.02°, maintaining the same accuracy as before, thus improving both durability and precision.

[0018] 3. The central channel achieves "one line for three uses": it can simultaneously pass through 8 sets of electrical wires, 2 hydraulic pipes, and cooling airflow or liquid flow, saving 40% of space compared to traditional designs. It is equivalent to "folding" the radiator, wiring harness, and oil circuit into a single pipe. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure;

[0020] Figure 2 This is a schematic diagram of the longitudinal section of the joint module;

[0021] Figure 3 This is a schematic diagram of a gear nodule;

[0022] Figure 4 This is a schematic diagram of the microstructure of the wear-resistant coating;

[0023] Figure 5 This is an exploded view of the overall structure;

[0024] Explanation of reference numerals: 1. Main housing; 2. Rear housing; 3. Frameless torque motor; 30. Coil; 31. Magnetic rotor assembly; 4. Hollow planetary reducer; 40. Gear ring; 41. Sun gear; 42. Planet gear; 43. Planet carrier; 44. Axial heat dissipation channel; 45. Spiral airflow guiding structure; 46. Roller bearing; 5. Gradient composite wear-resistant coating; 50. Chromium aluminum nitride; 51. Chromium aluminum nitride composite tungsten carbide; 52. Cobalt-doped tungsten carbide. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0026] like Figure 1-2 As shown, this embodiment provides a joint module combining a hollow planetary reducer 4 and a frameless torque motor 3. Its features include: a main housing 1, a rear housing 2, a frameless torque motor 3, and a hollow planetary reducer 4; the coil 30 of the frameless torque motor 3 is fixed to the inner wall of the main housing 1, and the magnetic rotor assembly 31 covers the outer side of the coil 30 and is coaxially and directly connected to the sun gear 41 of the hollow planetary reducer 4; the hollow planetary reducer 4 includes an internal gear ring 40, a sun gear 41, planet gears 42, and a planet carrier 43, with an axial heat dissipation channel 44 at the center and a spiral flow guiding structure 45 on the inner wall of the channel; the tooth surface of the planet gears 42 is coated with a gradient composite wear-resistant coating 5.

[0027] like Figure 2 As shown, in this embodiment, the spiral flow guide structure 45 runs through the central lifeline of the entire joint module. The inner wall of the channel is not smooth, but is precisely machined with the spiral flow guide structure 45, and fine threads are engraved on the inner wall of the pipe.

[0028] like Figure 3-4 As shown, in this embodiment, the meshing surface of the planetary gear is covered with a gradient composite wear-resistant coating 5. The gradient composite wear-resistant coating 5 consists of three layers. The first layer is chromium aluminum nitride 50, which can firmly grasp the planetary gear 42 substrate like strong glue, ensuring that the coating never falls off. The second layer is chromium aluminum nitride composite tungsten carbide 51, which acts like a tough buffer pad, combining hardness and toughness, absorbing impact and preventing the coating from cracking. The third layer is cobalt-doped tungsten carbide 52, which has a surface as hard as a diamond, and the cobalt element brings a self-lubricating effect, greatly reducing friction and wear, making the gear run as smoothly as silk.

[0029] In this embodiment, a cross roller bearing 46 is installed between the planetary carrier 43 and the main housing 1. The planetary carrier 43 serves as the power output end and supports the planetary gear 42 shaft through a high-precision bearing. The rear end of the planetary carrier 43 is supported on the main housing 1 through the cross roller bearing 46, bearing huge radial and axial forces to ensure the rigidity and rotational accuracy of the output end. The central hole forms part of the heat dissipation channel.

[0030] In this embodiment, the axial heat dissipation channel 44, after optimization of the wiring space, can simultaneously pass through 8 sets of power or signal harnesses to provide power and communication for downstream joints or end tools; 2 hydraulic pipes and cooling airflow or liquid flow provide power for end actuators (such as grippers, vacuum suction cups); the main heat dissipation airflow channel is as described above; this highly integrated design saves more than 40% of space compared to traditional joints that require separate cable conduits and cooling water pipes, making the wrist structure of the robotic arm exceptionally compact and flexible.

[0031] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to preferred embodiments, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present utility model. The implementation schemes in the above embodiments can also be further combined or replaced. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A joint module combining a hollow planetary reducer and a frameless torque motor, characterized in that: It includes a main housing (1), a rear housing (2), a frameless torque motor (3), and a hollow planetary reducer (4); The coil (30) of the frameless torque motor (3) is fixed to the inner wall of the rear housing (2), and the magnetic rotor assembly (31) covers the outside of the coil (30) and is coaxially fixedly connected to the sun gear (41) of the hollow planetary reducer (4). The hollow planetary reducer (4) includes an internal gear ring (40), a sun gear (41), planet gears (42) and a planet carrier (43), and has an axial heat dissipation channel (44) in the center, with a spiral flow guiding structure (45) on the inner wall of the channel; The planetary gear (42) has a gradient composite wear-resistant coating (5) on its meshing surface.

2. The joint module combining a hollow planetary reducer and a frameless torque motor according to claim 1, characterized in that: The pitch of the spiral guide structure (45) is 0.8-1.2 times the channel diameter, the groove depth is 0.3-0.5 mm, and the guide groove is inclined at an angle of 15° to 20° with the rotation direction of the planetary carrier (43).

3. The joint module combining a hollow planetary reducer and a frameless torque motor according to claim 1, characterized in that: The gradient composite wear-resistant coating (5) comprises three layers: the bonding layer is made of chromium aluminum nitride (50) material with a thickness of 3-5 μm; the transition layer is made of chromium aluminum nitride (50) composite tungsten carbide material with a thickness of 8-12 μm; and the working layer is made of cobalt-doped tungsten carbide material with a thickness of 10-15 μm.

4. The joint module combining a hollow planetary reducer and a frameless torque motor according to claim 1, characterized in that: A cross roller bearing (46) is installed between the planetary carrier (43) and the main housing (1). The bearing raceway surface is nitrided and has a hardness of not less than 900HV.

5. The joint module combining a hollow planetary reducer and a frameless torque motor according to claim 1, characterized in that: The axial heat dissipation channel (44) forms a composite cavity with the functions of heat dissipation airflow conduction and cable accommodation and organization through the spiral flow guiding structure (45) on the inner wall.

6. The joint module combining a hollow planetary reducer and a frameless torque motor according to claim 1, characterized in that: A sealing structure is provided between the main housing (1) and the rear housing (2). The sealing structure includes a multi-layer sealing ring and a dustproof ring. The multi-layer sealing ring is made of nitrile rubber material with different hardness. The surface of the dustproof ring is coated with polytetrafluoroethylene coating.

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