A hollow planetary reducer motor with encoder

Abstract

This utility model discloses a hollow planetary reducer motor with encoders, including a main housing, a rear housing, and a hollow planetary reducer. The rear housing houses a power board, a control board, an encoder connecting shaft, and dual encoders. The power board and control board are separated by ceramic insulating pillars. The hollow planetary reducer includes an internal gear ring, a sun gear, etc. The internal gear ring is connected to the stator, and the sun gear is connected to the rotor. 3-5 planetary gears are evenly distributed circumferentially for meshing transmission. The dual encoders are connected to the rotor and the output flange respectively via the connecting shaft, achieving precise feedback. The main and rear housings are made of high-strength aluminum alloy, with heat dissipation fins on the rear housing. The control board integrates a communication protocol chip, supporting automatic zero-point calibration. The output flange has a standard robot interface, a large-diameter hollow channel, and a wear-resistant insulating layer on the inner wall, meeting the needs of various complex scenarios and combining efficient power transmission with precise control performance.

Description

Technical Field

[0001] This utility model relates to the field of robot joint drive technology, and is particularly applicable to hollow planetary reducer motors for industrial robots, collaborative robots and precision servo systems, integrating dual encoder closed-loop control and hollow wiring function. Background Technology

[0002] In traditional robot joint modules, the separation of the motor and reducer results in excessive axial length, requiring external wiring that is prone to wear and occupies space. While planetary reducers can be miniaturized, their solid central structure restricts cable routing and insufficient rigidity can lead to positioning errors. Existing single-encoder solutions struggle to simultaneously monitor the rotor and output positions, affecting closed-loop accuracy. Furthermore, the lack of isolation between the power board and control board can cause electromagnetic interference. Utility Model Content

[0003] The purpose of this invention is to provide a hollow planetary reducer motor with an encoder to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a hollow planetary reducer motor with an encoder, comprising a main housing, a rear housing, and a hollow planetary reducer; a power board, a control board, an encoder connecting shaft, and dual encoders are installed inside the rear housing, and an insulating column is provided between the control board and the power board; the hollow planetary reducer is composed of an internal gear ring, a sun gear, planet gears, and a planetary gear set; a hollow channel is provided through the axial center of the planetary reducer; the internal gear ring is connected to the stator, the sun gear is fixedly connected to the motor rotor, and the planet gears mesh between the sun gear and the internal gear ring.

[0005] Furthermore, the main housing and the rear housing are made of high-strength aluminum alloy and have heat dissipation fins on their surfaces.

[0006] Furthermore, the insulating pillar is made of ceramic material and vertically penetrates the mounting holes of the control board and the power board.

[0007] Furthermore, the control board integrates EtherCAT and CANopen communication protocol chips, supporting automatic zero-point calibration before operation.

[0008] Furthermore, the number of planetary gears is 3-5, evenly distributed circumferentially on the outer side of the sun gear.

[0009] Furthermore, the output flange end face is provided with a standard robot interface protrusion.

[0010] Furthermore, the diameter of the hollow channel is not less than 1.5 times the diameter of the motor shaft, and the inner wall of the channel is covered with a wear-resistant insulating layer.

[0011] Compared with the prior art, the advantages and positive effects of this utility model are as follows:

[0012] This invention utilizes a hollow channel design to allow the cable and air tube to pass inside, reducing the axial dimension of the joint module by 30%. It employs dual encoder closed-loop feedback to eliminate transmission chain errors and achieve a positioning accuracy of ±0.01°. The planetary carrier and output flange are combined with a lightweight aluminum alloy housing, reducing weight by 25% while increasing torsional stiffness to 1.8 times that of comparable products. Insulating pillars physically isolate the power board and control board, blocking current interference and reducing communication error rate by 90%. The control board integrates EtherCAT and CANopen communication protocol chips, enabling automatic zero-point calibration and improving deployment efficiency by 50%, achieving a unified approach of high rigidity, high precision, and intelligent control. Attached Figure Description

[0013] Figure 1 This is an exploded view of the entire structure.

[0014] Figure 2 This is a diagram of the overall structure.

[0015] Figure 3 This is a schematic diagram showing the installation location of the dual encoders.

[0016] Explanation of reference numerals: 1. Main housing; 2. Rear housing; 20. Power board; 21. Control board; 22. Encoder connecting shaft; 23. Dual encoder; 230. Motor end encoder; 231. Output end encoder; 24. Insulating column; 3. Hollow planetary reducer; 30. Internal gear ring; 31. Sun gear; 32. Planet gears; 33. Planetary carrier; 301. Stator; 302. Motor rotor; 34. Output flange; 35. Hollow channel; 4. Heat dissipation fins; 5. Protruding hole. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0018] like Figures 1-2As shown, this utility model provides a technical solution: a hollow planetary reducer motor with encoder, including a main housing 1, a rear housing 2, and a hollow planetary reducer 3; a power board 20, a control board 21, an encoder connecting shaft 22, and a dual encoder 23 are installed inside the rear housing 2, and an insulating column 24 is provided between the control board 21 and the power board 20; the hollow planetary reducer 3 is composed of an internal gear ring 30, a sun gear 31, planet gears 32, and a planet carrier 33; a hollow channel 35 is provided through the axial center of the planetary reducer; the internal gear ring 30 is connected to the stator 301, the sun gear 31 is fixedly connected to the motor rotor 302, and the planet gears 32 mesh between the sun gear 31 and the internal gear ring 30.

[0019] In this embodiment, the main housing 1 and the rear housing 2 are made of high-strength aluminum alloy casting. The surface of the rear housing 2 is machined with radial heat dissipation fins 4. The two housings are positioned by a stop, and fluororubber O-rings are embedded in the mating surface. The eight sets of bolts are tightened in three steps in a diagonal sequence.

[0020] In this embodiment, the hollow planetary reducer 3 is pressed into the main housing 1 after the stator 301 is frozen with liquid nitrogen and then heat-fitted to the inner wall of the stator 301. The rotor is directly connected to the sun gear 31 through an involute spline, and then four planet gears 32 are evenly distributed around the outside of the sun gear 31 and mounted on the pin shaft of the planet carrier 33. The planet gears 32 are fitted with internal gear rings 30, and the tooth backlash is adjusted to 0.06mm. The exposed end face of the output flange 34 is provided with two robot interface protrusion holes 5.

[0021] In this embodiment, a power board 20 is fixed inside the rear housing 2, on which an alumina ceramic insulating column 24 is vertically mounted. A control board 21 is connected to the insulating column 24 and locked to the interior of the rear housing 2 with a nylon nut. The control board 21 integrates EtherCAT and CANopen protocols and automatically performs zero-point calibration upon power-up. The power board and control board are existing technologies and will not be elaborated upon here. The motor-end encoder 230 is connected to the rotor tail end via a coupling to monitor the rotor position in real time; the output-end encoder 231 has its grating disk fixedly connected to the output flange 34 end face to detect the actual displacement of the load.

[0022] In this embodiment, the planetary carrier 33 and the output flange 34 are formed by five-axis machining of a single piece of aluminum alloy, eliminating the gap of bolt connection in the split structure. Under a load of 200Nm, the torsion angle is only 0.05°, and the stiffness is increased by 44%. The hollow channel 35 has a diameter of Φ15mm and an inner wall electrostatically sprayed with a 50μm wear-resistant polytetrafluoroethylene insulating layer. The friction coefficient is <0.05, and a Φ12mm wire harness can pass through.

[0023] The working principle of this utility model is as follows: When the motor is powered on, the rotating magnetic field generated by the stator 301 winding drives the rotor to rotate at the rated speed. Simultaneously, a PT100 temperature sensor embedded in the stator 301 winding monitors the temperature rise in real time. The rotor directly drives the sun gear 31 to rotate synchronously via an involute spline. The sun gear 31, acting as an input gear, drives the three circumferentially distributed planetary gears 32 to rotate. Since the internal gear ring 30 is connected to the stator 301, the planetary gears 32 revolve around the internal gear ring 30 while rotating, ultimately driving the planet carrier 33 and the output flange 34 to output the reduced torque. The reduction ratio is determined by the ratio of the number of teeth on the gear ring to the number of teeth on the sun gear 31. When the input is 3000 rpm, the output speed is 428.6 rpm, achieving efficient torque amplification. Simultaneously, the motor-end encoder 230 monitors the rotor angular displacement θ1 in real time, and the output-end encoder 231 synchronously detects the actual rotation angle θ2 of the output flange 34. The control board 21 has a built-in ARM processor. The Cortex-M7 processor calculates the theoretical output angle θ1' = θ1 / i, compares it with θ2 to obtain the position deviation Δθ, and dynamically adjusts the PWM output phase of the power board 20 through a PID algorithm to bring Δθ to within ±0.01°, thus achieving error compensation. Upon initial power-up, the calibration program is automatically executed, controlling the output flange 34 to rotate at low speed to the mechanical limit block. At this moment, the encoder 231 count value at the output end can be set to absolute zero, eliminating accumulated assembly errors. The external wiring harness can pass through the waterproof connector of the rear housing 2, through the axially penetrating hollow channel 35, directly to the front end of the output flange 34. The PTFE wear-resistant insulation layer on the inner wall of the channel ensures that the cable will not wear after 100,000 insertions and removals, and there are no sharp-angle bends throughout the entire process, also avoiding signal attenuation and short-circuit risks.

[0024] 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 hollow planetary reducer motor with an encoder, comprising a main housing (1), a rear housing (2), and a hollow planetary reducer (3); characterized in that: The power board (20), control board (21), encoder connecting shaft (22) and dual encoder (23) are installed inside the rear housing (2). An insulating column (24) is provided between the control board (21) and the power board (20). The hollow planetary reducer (3) is composed of an internal gear ring (30), a sun gear (31), planet gears (32) and a planet carrier (33). A hollow channel (35) is provided through the axial center of the planetary reducer. The internal gear ring (30) is connected to the stator (301), the sun gear (31) is fixedly connected to the motor rotor (302), and the planet gears (32) mesh between the sun gear (31) and the internal gear ring (30).

2. A hollow planetary reducer motor with encoder according to claim 1, characterized in that: The dual encoder (23) includes a motor end encoder (230) and an output end encoder (231), which are connected to the rotor and the output flange (34) respectively through the encoder connecting shaft (22).

3. A hollow planetary reducer motor with encoder according to claim 1, characterized in that: The main housing (1) and the rear housing (2) are made of high-strength aluminum alloy components, wherein the surface of the rear housing (2) is provided with heat dissipation fins (4).

4. A hollow planetary reducer motor with encoder according to claim 1, characterized in that: The insulating column (24) is a ceramic component that vertically penetrates the mounting holes of the control board (21) and the power board (20).

5. A hollow planetary reducer motor with encoder according to claim 1, characterized in that: The control board (21) integrates EtherCAT and CANopen communication protocol chips.

6. A hollow planetary reducer motor with encoder according to claim 1, characterized in that: The number of planetary gears (32) is 3-5, and they are evenly distributed around the outer side of the sun gear (31).

7. A hollow planetary reducer motor with encoder according to claim 2, characterized in that: The output flange (34) has multiple protrusions (5) on its end face.

8. A hollow planetary reducer motor with encoder according to claim 1, characterized in that: The diameter of the hollow channel (35) is not less than 1.5 times the diameter of the motor shaft, and the inner wall of the channel is covered with a wear-resistant insulating layer.

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