Articulated actuator and its two-stage planetary reduction mechanism

Abstract

The utility model discloses a two-stage planetary reduction mechanism, including coaxial setting primary sun wheel and secondary sun wheel, and primary sun wheel and secondary sun wheel outer cover are provided with long gear ring, and long gear ring extends from secondary sun wheel to primary sun wheel along the axial direction, and long gear ring is equipped with primary planetary gear and primary planet carrier for installing primary planetary gear between primary sun wheel and primary sun wheel, and long gear ring is equipped with secondary planetary gear and secondary planet carrier for installing secondary planetary gear between long gear ring and secondary sun wheel, and the inner wall of long gear ring is equipped with primary internal tooth and secondary internal tooth at intervals, and primary planetary gear is engaged with primary sun wheel and primary internal tooth respectively, and secondary planetary gear is engaged with secondary sun wheel and secondary internal tooth respectively, and long gear ring is fixedly arranged, and primary planet carrier is transmission connection with secondary sun wheel. The utility model discloses a joint actuator. The joint actuator and two-stage planetary reduction mechanism thereof not only can realize the requirement of larger transmission ratio, but also will not increase the size.

Description

Technical Field

[0001] This utility model belongs to the field of robot technology, specifically a joint actuator and its two-stage planetary reduction mechanism. Background Technology

[0002] As the core power component of a robot system, the joint actuator plays a crucial role in converting electrical energy into mechanical motion. Its performance directly affects the robot's motion accuracy, load capacity, response speed, and overall reliability. Technically, a typical joint actuator usually consists of modules such as a drive motor, reduction gear, sensor system, and control unit. These components are precisely integrated to achieve functions such as torque amplification, motion conversion, and closed-loop control. With the continuous expansion of robot applications, from industrial manufacturing to medical services, from space exploration to home services, the performance requirements for joint actuators are becoming increasingly diversified and stringent.

[0003] Mechanically reduced-speed articulated actuators have long dominated the field of industrial robots. Their core technology utilizes gear meshing to reduce the motor's output speed and amplify its torque. These actuators typically employ a three-stage architecture: the high-speed stage provides the initial power to the servo motor; the intermediate stage uses a precision reducer to achieve speed and torque variation; and the output stage integrates position / torque sensors to form a closed-loop control. Based on the type of reduction mechanism, mainstream solutions can be divided into three main categories: harmonic reducers, planetary reducers, and RV reducers, each with distinct performance characteristics and applicable scenarios. Among them, planetary reducers employ a multi-stage parallel gear splitting structure, offering advantages in high rigidity and high load capacity, and are commonly found in heavy-duty industrial robots. However, achieving a large transmission ratio with existing planetary reducers leads to an increase in radial dimensions, limiting their application in space-constrained environments. Summary of the Invention

[0004] In view of this, the purpose of this utility model is to provide a joint actuator and its two-stage planetary reduction mechanism, which can not only meet the requirements of a large transmission ratio, but also does not increase the size.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] This invention first proposes a two-stage planetary reduction mechanism, including a first-stage sun gear and a second-stage sun gear arranged coaxially. The first-stage sun gear and the second-stage sun gear are fitted with a long toothed ring, which extends axially from the second-stage sun gear to the first-stage sun gear. A first-stage planetary gear and a first-stage planet carrier for mounting the first-stage planetary gear are provided between the long toothed ring and the first-stage sun gear. A second-stage planetary gear and a second-stage planet carrier for mounting the second-stage planetary gear are provided between the long toothed ring and the second-stage sun gear.

[0007] The inner wall of the long gear ring is provided with a first-level internal tooth and a second-level internal tooth at intervals. The first-level planetary gear meshes with the first-level sun gear and the first-level internal tooth respectively, and the second-level planetary gear meshes with the second-level sun gear and the second-level internal tooth respectively.

[0008] The long gear ring is fixedly installed, and the first-stage planetary carrier is connected to the second-stage sun gear via a transmission.

[0009] Furthermore, the number of teeth on the first-stage planetary gear and the second-stage planetary gear may be equal or unequal; the number of teeth on the first-stage sun gear and the second-stage sun gear may be equal or unequal; and the number of teeth on the first-stage internal gear and the second-stage internal gear may be equal or unequal.

[0010] Furthermore, the primary planetary carrier is disposed between the primary planetary gears and the secondary planetary gears, and the primary planetary carrier rotates synchronously with the secondary sun gear.

[0011] Furthermore, the axis of rotation of the first-stage planetary carrier and the second-stage sun gear are integrated.

[0012] This utility model also proposes a joint actuator, including a housing, a motor assembly inside the housing, the motor assembly including a stator and a rotor sleeved outside the stator, the stator having a central through hole, the two-stage planetary reduction mechanism described above being installed in the central through hole; a long gear ring sleeved in the central through hole and fixedly connected to the housing, the first-stage sun gear being drively connected to the rotor, and an output flange being provided on the second-stage planetary carrier.

[0013] Furthermore, the housing includes a shell and an end cap mounted on the shell.

[0014] Furthermore, a connecting disc is connected to the rotor, and the connecting disc is located between the housing and the stator; the center of the connecting disc is provided with an axially extending connecting portion, and a connecting through hole is provided in the connecting portion, and the shaft of the first-stage sun gear is installed in the connecting through hole.

[0015] Furthermore, the housing is provided with a clearance hole to accommodate the connecting part, and the inner diameter of the long gear ring is larger than the outer diameter of the connecting part; deep groove ball bearings are respectively provided between the connecting part and the housing and the long gear ring.

[0016] Furthermore, the long toothed ring is fixedly connected to the end cap, and a crossed roller bearing is provided between the long toothed ring and the end cap and the secondary planetary carrier.

[0017] Furthermore, a magnetic bead is provided at the end of the central through hole facing away from the first-stage sun gear.

[0018] The beneficial effects of this utility model are as follows:

[0019] This utility model discloses a joint actuator by setting up a two-stage planetary reducer. The rotor is connected to a first-stage sun gear, and the first-stage planetary carrier is connected to a second-stage sun gear. An output flange is provided on the second-stage planetary carrier. Thus, first-stage reduction is achieved by the first-stage planetary gears meshing with the first-stage internal gear and the first-stage sun gear of the long-tooth ring. Second-stage reduction is achieved by the second-stage planetary gears meshing with the second-stage internal gear and the second-stage sun gear of the long-tooth ring. The total reduction ratio of the two-stage planetary reducer is the product of the first-stage and second-stage reduction ratios. This two-stage reduction can meet the requirement of a large transmission ratio and can reduce the transmission ratios of the first and second stages respectively, thereby reducing the radial dimension of the planetary reducer. Furthermore, by placing the two-stage planetary reducer within the central through-hole of the stator... Furthermore, by sharing a single long gear ring between the first and second stage reduction gears, the axial structure of the two-stage planetary reducer becomes more compact, resulting in a smaller axial dimension of the joint actuator. By interleaving the first and second stage internal teeth within the long gear ring, the first-stage reduction gear ratio can be flexibly adjusted by changing the number of teeth on the first-stage internal teeth, the first-stage planetary gears, and the first-stage sun gear. Similarly, the second-stage reduction gear ratio can be flexibly adjusted by changing the number of teeth on the second-stage internal teeth, the second-stage planetary gears, and the second-stage sun gear. Adjusting the first and second stage reduction gear ratios also allows for flexible adjustment of the load capacity of the first and second stage reduction gears to meet load requirements. In summary, the joint actuator of this invention not only achieves a larger transmission ratio but also reduces the radial dimension without increasing the axial dimension. Attached Figure Description

[0020] To make the objectives, technical solutions, and beneficial effects of this utility model clearer, the following drawings are provided for illustration:

[0021] Figure 1 This is a schematic diagram of the structure of an embodiment of the joint actuator of this utility model;

[0022] Figure 2 for Figure 1 Left-axis projection;

[0023] Figure 3 for Figure 1 The right axonometric projection.

[0024] 10-Housing; 101-Protrusion; 102-Connecting hole; 11-End cover; 12-Stator; 13-Rotor; 14-First-stage sun gear; 15-Second-stage sun gear; 16-Long gear ring; 161-First-stage internal gear; 162-Second-stage internal gear; 17-First-stage planetary gear; 18-First-stage planetary carrier; 19-Second-stage planetary gear; 20-Second-stage planetary carrier; 21-Output flange; 22-Connecting disc; 221-Connecting part; 222-Connecting through hole; 23-Deep groove ball bearing; 24-Deep groove ball bearing; 25-Crossed roller bearing; 26-Magnetic bead; 27-Circuit board. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments are not intended to limit the present invention.

[0026] like Figure 1 As shown, the joint actuator of this embodiment includes a housing, within which a motor assembly is housed. In this embodiment, the housing includes a shell 10 and an end cover 11 mounted on the shell 10, with the end cover 11 and the shell 10 fixedly connected. The motor assembly includes a stator 12 and a rotor 13 sleeved outside the stator 12. The stator 12 has a central through hole, within which a two-stage planetary reducer is installed. In this embodiment, the two-stage planetary reducer includes a first-stage sun gear 14 and a second-stage sun gear 15 coaxially arranged. A long gear ring 16 is sleeved on the first-stage sun gear 14 and the second-stage sun gear 15, extending axially from the second-stage sun gear 15 to the first-stage sun gear 14. A first-stage planetary gear 17 and a first-stage planet carrier 18 for mounting the first-stage planetary gear 17 are provided between the long gear ring 16 and the first-stage sun gear 14. A second-stage planetary gear 19 and a second-stage planet carrier 20 for mounting the second-stage planetary gear 19 are provided between the long gear ring 16 and the second-stage sun gear 15. Specifically, the inner wall of the long tooth ring 16 is provided with a first-level internal tooth 161 and a second-level internal tooth 162. The first-level planetary gear 17 meshes with the first-level sun gear 14 and the first-level internal tooth 161 respectively, and the second-level planetary gear 19 meshes with the second-level sun gear 15 and the second-level internal tooth 162 respectively.

[0027] In this embodiment, the long gear ring 16 is fixedly installed, and the primary planetary carrier 18 is connected to the secondary sun gear 15 via a transmission connection. Specifically, the primary planetary carrier 18 is positioned between the primary planetary gear 17 and the secondary planetary gear 19, and the primary planetary carrier 18 and the secondary sun gear 15 rotate synchronously. In a preferred embodiment, the shafts of the primary planetary carrier 18 and the secondary sun gear 19 are integrated, which simplifies the structure.

[0028] In this embodiment, the long gear ring 16 is fitted inside the central through hole and fixedly connected to the outer casing. The first-stage sun gear 14 is driven by the rotor 13, and the second-stage planetary carrier 20 is provided with an output flange 21. Specifically, a connecting disc 22 is connected to the rotor 13, and the connecting disc 22 is located between the housing 10 and the stator 12. The center of the connecting disc 22 is provided with an axially extending connecting portion 221, and a connecting through hole 222 is provided inside the connecting portion 221. The shaft of the first-stage sun gear 14 is installed in the connecting through hole 222. In this embodiment, the first-stage sun gear 14 rotates synchronously with the rotor 13 through the connecting disc 22. In this embodiment, a magnetic bead 26 is provided at the end of the connecting through hole 222 facing away from the first-stage sun gear 14.

[0029] In this embodiment, the housing 10 is provided with a clearance hole for the clearance connecting portion 221, and the inner diameter of the long gear ring 16 is larger than the outer diameter of the connecting portion 221. A deep groove ball bearing 23 and a deep groove ball bearing 24 are respectively provided between the connecting portion 221 and the housing 10 and the long gear ring 16.

[0030] In this embodiment, the long toothed ring 16 is fixedly connected to the end cap 11, and a cross roller bearing 25 is provided between the long toothed ring 16, the end cap 11 and the secondary planetary carrier 20.

[0031] Specifically, in this embodiment, the number of teeth on the first-stage planetary gear 17 and the second-stage planetary gear 19 are equal, the number of teeth on the first-stage sun gear 14 and the second-stage sun gear 15 are equal, and the number of teeth on the first-stage internal gear 161 and the second-stage internal gear 162 are equal. That is, in this embodiment, the transmission ratios of the first-stage reduction gear and the second-stage reduction gear are the same. Of course, in some other embodiments, the transmission ratios of the first-stage reduction gear and the second-stage reduction gear can also be different. For example, the number of teeth on the first-stage planetary gear 17 and the second-stage planetary gear 19 can be set to be unequal, the number of teeth on the first-stage sun gear 14 and the second-stage sun gear 15 can be set to be unequal, and the number of teeth on the first-stage internal gear 161 and the second-stage internal gear 162 can be set to be unequal, which will not be elaborated further. Specifically, the first-stage reduction gear ratio can be flexibly adjusted by adjusting the number of teeth on the first-stage internal gear 161, the first-stage planetary gear 17, and the first-stage sun gear 14; similarly, the second-stage reduction gear ratio can be flexibly adjusted by adjusting the number of teeth on the second-stage internal gear 162, the second-stage planetary gear 19, and the second-stage sun gear 15; by adjusting the first-stage and second-stage reduction gear ratios, the load capacity of the first-stage and second-stage reduction gears can also be flexibly adjusted to meet load requirements.

[0032] In this embodiment, the end face of the housing 10 is provided with a protrusion 101, and the protrusion 101 is provided with connecting holes 102 at intervals. The protrusion 101 and the connecting holes 102 are used to mount the circuit board 27, etc., and will not be described in detail.

[0033] In this embodiment, the joint actuator uses a two-stage planetary reducer to drive the rotor 13 to the first-stage sun gear 14 and the first-stage planetary carrier 18 to the second-stage sun gear 15. An output flange 21 is provided on the second-stage planetary carrier 20. Thus, the first-stage planetary gear 17 meshes with the long gear ring 16 and the first-stage sun gear 14 to achieve first-stage reduction, and the second-stage planetary gear 19 meshes with the long gear ring 16 and the second-stage sun gear 15 to achieve second-stage reduction. The total reduction ratio of the two-stage planetary reducer is the product of the first-stage reduction ratio and the second-stage reduction ratio. That is, the two-stage reduction can meet the requirement of a large transmission ratio and can reduce the transmission ratio of the first-stage reduction and the second-stage reduction respectively, thereby reducing the radial dimension of the planetary reducer. By setting the two-stage planetary reducer in the central through hole of the stator 12 and making the first-stage reduction and the second-stage reduction share a long gear ring 16, the axial structure of the two-stage planetary reducer can be made more compact, and the axial dimension of the joint actuator can be smaller. By arranging primary internal teeth 161 and secondary internal teeth 162 at intervals within the long gear ring 16, the primary reduction gear ratio can be flexibly adjusted by changing the number of teeth on the primary internal teeth 161, primary planetary gears 17, and primary sun gear 14. Similarly, the secondary reduction gear ratio can be flexibly adjusted by changing the number of teeth on the secondary internal teeth 162, secondary planetary gears 19, and secondary sun gear 15. Furthermore, by adjusting the primary and secondary reduction gear ratios, the load capacity of the primary and secondary reduction gears can also be flexibly adjusted to meet load requirements. In summary, the joint actuator of this embodiment not only achieves a larger transmission ratio but also reduces the radial dimension without increasing the axial dimension.

[0034] The above-described embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A two-stage planetary reduction mechanism, characterized in that: It includes a first-stage sun gear and a second-stage sun gear arranged coaxially. The first-stage sun gear and the second-stage sun gear are fitted with a long toothed ring. The long toothed ring extends axially from the second-stage sun gear to the first-stage sun gear. A first-stage planetary gear and a first-stage planet carrier for mounting the first-stage planetary gear are provided between the long toothed ring and the first-stage sun gear. A second-stage planetary gear and a second-stage planet carrier for mounting the second-stage planetary gear are provided between the long toothed ring and the second-stage sun gear. The inner wall of the long gear ring is provided with a first-level internal tooth and a second-level internal tooth at intervals. The first-level planetary gear meshes with the first-level sun gear and the first-level internal tooth respectively, and the second-level planetary gear meshes with the second-level sun gear and the second-level internal tooth respectively. The long gear ring is fixedly installed, and the first-stage planetary carrier is connected to the second-stage sun gear via a transmission.

2. The two-stage planetary reduction mechanism according to claim 1, characterized in that: The number of teeth on the first-stage planetary gear and the second-stage planetary gear may be equal or unequal; the number of teeth on the first-stage sun gear and the second-stage sun gear may be equal or unequal; the number of teeth on the first-stage internal gear and the second-stage internal gear may be equal or unequal.

3. The two-stage planetary reduction mechanism according to claim 1, characterized in that: The primary planetary carrier is positioned between the primary planetary gears and the secondary planetary gears, and the primary planetary carrier rotates synchronously with the secondary sun gear.

4. The two-stage planetary reduction mechanism according to claim 1, characterized in that: The primary planetary carrier and the secondary sun gear are integrated into one unit.

5. A joint actuator, characterized in that: The device includes a housing, within which a motor assembly is provided. The motor assembly includes a stator and a rotor fitted outside the stator. The stator has a central through hole, and a two-stage planetary reduction mechanism as described in any one of claims 1-4 is installed in the central through hole. A long gear ring is fitted inside the central through hole and fixedly connected to the housing. The first-stage sun gear is driven by the rotor. An output flange is provided on the second-stage planetary carrier.

6. The joint actuator according to claim 5, characterized in that: The outer casing includes a housing and end caps mounted on the housing.

7. The joint actuator according to claim 6, characterized in that: The rotor is connected to a connecting disc, which is located between the housing and the stator; the center of the connecting disc is provided with an axially extending connecting portion, and the connecting portion is provided with a connecting through hole, and the shaft of the first-stage sun gear is installed in the connecting through hole.

8. The joint actuator according to claim 7, characterized in that: The housing is provided with a clearance hole to accommodate the connecting part, and the inner diameter of the long gear ring is larger than the outer diameter of the connecting part; deep groove ball bearings are respectively provided between the connecting part and the housing and the long gear ring.

9. The joint actuator according to claim 6, characterized in that: The long gear ring is fixedly connected to the end cap, and a cross roller bearing is provided between the long gear ring and the end cap and the secondary planetary carrier.

10. The joint actuator according to claim 5, characterized in that: A magnetic bead is provided at the end of the central through hole facing away from the first-stage sun gear.

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