Joint actuator and gear reducer thereof

Abstract

The utility model discloses a gear reducer which comprises a sun wheel shaft, a planet carrier and a gear ring. A sun gear is arranged on the sun gear shaft; the planet carrier comprises an internal planet carrier and an output planet carrier, the internal planet carrier is fixedly connected with the output planet carrier, a plurality of planet wheel shafts are arranged between the internal planet carrier and the output planet carrier, and large planet gears meshed with the sun wheel and small planet gears meshed with the gear ring are arranged on the planet wheel shafts; the pitch diameter of the large planetary gear is larger than that of the small planetary gear. The utility model further discloses a joint actuator which comprises a shell, a motor assembly and the gear reducer are arranged in the shell, the motor assembly comprises a stator and a rotor arranged in the stator in a sleeved mode, a center through hole is formed in the rotor, a transmission part synchronously rotating with the rotor is arranged in the center through hole, and the transmission part is in transmission connection with the sun wheel shaft. And the gear ring is fixedly mounted in the shell. According to the joint actuator, the radial size cannot be increased under the condition that the requirement of large transmission ratio is met.

Description

Technical Field

[0001] This utility model belongs to the field of robot technology, specifically a joint actuator and its gear reducer. 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 gear reducer that can meet the requirements of a large transmission ratio without increasing the radial dimension.

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

[0006] This utility model discloses a gear reducer, comprising a sun gear shaft, a planet carrier, and a gear ring;

[0007] The sun gear shaft is provided with a sun gear; the planet carrier includes an inner planet carrier and an output planet carrier, the inner planet carrier and the output planet carrier are fixedly connected, and a plurality of planet gear shafts are provided between the inner planet carrier and the output planet carrier. The planet gear shaft is provided with a large planetary gear that meshes with the sun gear and a small planetary gear that meshes with the ring gear. The pitch circle diameter of the large planetary gear is larger than the pitch circle diameter of the small planetary gear.

[0008] Furthermore, a clearance is provided between the internal planetary carrier and the output planetary gear carrier to accommodate the large planetary gear.

[0009] Furthermore, the output planetary carrier is equipped with an output flange.

[0010] This utility model also proposes a joint actuator, including a housing, in which a motor assembly and a gear reducer as described above are provided. The motor assembly includes a stator and a rotor sleeved in the stator. The rotor has a central through hole, and a transmission component that rotates synchronously with the rotor is provided in the central through hole. The transmission component is connected to the sun gear shaft for transmission. The gear ring is fixedly installed in the housing.

[0011] Furthermore, the housing includes a shell and an end cap mounted on the shell.

[0012] Furthermore, the transmission component includes a transmission shaft, one end of which is provided with a first bearing between itself and the housing, and the second end of which is provided with a second bearing between itself and the internal planetary carrier, and the transmission shaft rotates synchronously with the sun gear shaft.

[0013] Furthermore, the transmission shaft has a transmission part in the middle that is connected to the rotor.

[0014] Furthermore, a third bearing is provided between the end cover and the output planetary carrier, and the third bearing is a crossed roller bearing.

[0015] Furthermore, the pitch circle diameter of the planetary gear is:

[0016]

[0017] Where: d2 is the pitch circle diameter of the planetary gear; d 2a d1 is the pitch circle diameter of the planetary gear; d2 is the pitch circle diameter of the sun gear; D is the inner diameter of the housing corresponding to the planetary gear position; Δ is the radial width of the clearance reserved between the planetary gear and the housing.

[0018] Furthermore, the pitch circle diameter of the asteroid gear is:

[0019] d3 = d4 - (d1 + d2)

[0020] Where: d3 is the pitch circle diameter of the asteroid gear; d4 is the pitch circle diameter of the gear ring.

[0021] The beneficial effects of this utility model are as follows:

[0022] This utility model's articulated actuator, through the inclusion of a gear reducer, connects the rotor and sun gear shaft via a transmission component. A large planetary gear and a small planetary gear are respectively mounted on the primary planetary shaft, meshing with the sun gear and ring gear. Thus, primary reduction is achieved through the transmission between the large planetary gear and the sun gear, while secondary reduction is achieved through the transmission between the small planetary gear and the ring gear. The total reduction ratio of the gear reducer is the product of the primary and secondary reduction ratios, satisfying the requirement for a large transmission ratio and reducing the magnitude of both the primary and secondary reduction ratios, thereby reducing the radial dimension of the planetary reducer. In summary, this utility model's articulated actuator and its gear reducer, while meeting the requirement of a large transmission ratio, do not increase the radial dimension. Attached Figure Description

[0023] To make the objectives, technical solutions, and beneficial effects of this utility model clearer, the following drawings are provided for illustration:

[0024] Figure 1 This is a schematic diagram of the structure of an embodiment of the joint actuator of this utility model;

[0025] Figure 2 for Figure 1 Left-axis projection;

[0026] Figure 3 for Figure 1 The right axonometric projection.

[0027] Explanation of reference numerals in the attached figures:

[0028] 10-House; 11-End cover; 121-Stator; 122-Rotor; 13-Sun gear shaft; 14-Sun gear; 15-Ring gear; 16-Internal planetary carrier; 17-Output planetary carrier; 18-Output flange; 19-Planet gear shaft; 20-Large planetary gear; 21-Small planetary gear; 22-Reserved clearance; 23-Central through hole; 24-Transmission component; 241-Transmission shaft; 242-Transmission unit; 25-First bearing; 26-Second bearing; 27-Third bearing. Detailed Implementation

[0029] 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.

[0030] like Figure 1As shown, the joint actuator of this embodiment includes a housing, within which a motor assembly and a gear reducer are housed. In this embodiment, the housing includes a shell 10 and an end cap 11 mounted on the shell 10, the end cap 11 being fixedly connected to the shell 10. The motor assembly includes a stator 121 and a rotor 122 sleeved within the stator 121.

[0031] In this embodiment, the gear reducer includes a sun gear shaft 13, a planet carrier, and a ring gear 15. Specifically, a sun gear 14 is mounted on the sun gear shaft 13. The ring gear 15 is fixedly installed inside the housing. The planet carrier includes an inner planet carrier 16 and an output planet carrier 17, with the inner planet carrier 16 fixedly connected to the output planet carrier 17. An output flange 18 is provided on the output planet carrier 17. Specifically, a plurality of planet gear shafts 19 are provided between the inner planet carrier 16 and the output planet carrier 17. Each planet gear shaft 19 has a large planetary gear 20 that meshes with the sun gear 14 and a small planetary gear 21 that meshes with the ring gear 15. The pitch circle diameter of the large planetary gear 20 is larger than that of the small planetary gear 21.

[0032] Furthermore, in order to set the pitch circle diameter of the large planetary gear 20 to be larger and to avoid the limitation of the planet carrier size being the large planetary gear 20, this embodiment provides a clearance gap between the inner planet carrier 16 and the output planet carrier 17 to accommodate the large planetary gear.

[0033] In this embodiment, the rotor 122 has a central through hole 23, and a transmission component 24 that rotates synchronously with the rotor 122 is provided in the central through hole 23. The transmission component 24 is connected to the sun gear shaft 13. Specifically, the transmission component 24 includes a transmission shaft 241. One end of the transmission shaft 241 is provided with a first bearing 25 between it and the housing 10, and the second end is provided with a second bearing 26 between it and the internal planetary carrier 16. The transmission shaft 241 rotates synchronously with the sun gear shaft 13, and the first bearing 25 and the second bearing 26 are deep groove ball bearings. In this embodiment, the transmission shaft 241 has a transmission part 242 connected to the rotor 122 in the middle.

[0034] In this embodiment, a third bearing 27 is provided between the end cover 11 and the output planetary carrier 17, and the third bearing 27 is a crossed roller bearing.

[0035] Specifically, in this embodiment, in order to maximize the transmission ratio between the large planetary gear 20 and the sun gear 14, the pitch circle diameter of the large planetary gear is:

[0036]

[0037] Where: d2 is the pitch circle diameter of planetary gear 20; d 2ad1 is the pitch circle diameter of the planetary gear 20; d1 is the pitch circle diameter of the sun gear 14; D is the inner diameter of the outer casing 10 at the position corresponding to the planetary gear 20; Δ is the radial width of the reserved gap 22 between the planetary gear 20 and the outer casing 10.

[0038] Similarly, the pitch circle diameter of asteroid gear 21 is:

[0039] d3 = d4 - (d1 + d2)

[0040] Where: d3 is the pitch circle diameter of asteroid gear 21; d4 is the pitch circle diameter of gear ring 15.

[0041] The joint actuator of this embodiment uses a gear reducer to connect the rotor and the sun gear shaft via a transmission component. A large planetary gear and a small planetary gear are respectively mounted on the first-stage planetary shaft, meshing with the sun gear and the ring gear. Thus, the transmission between the large planetary gear and the sun gear achieves first-stage reduction, and the transmission between the small planetary gear and the ring gear achieves second-stage reduction. The total reduction ratio of the gear reducer is the product of the first-stage and second-stage reduction ratios, which satisfies the requirement for a large transmission ratio and reduces the magnitude of the first-stage and second-stage reduction ratios, thereby reducing the radial dimension of the planetary reducer. In summary, this utility model's joint actuator and its gear reducer meet the requirement of a large transmission ratio without increasing the radial dimension.

[0042] 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 gear reducer, characterized in that: Including the sun gear axle, planet carrier, and ring gear; The sun gear shaft is provided with a sun gear; the planet carrier includes an inner planet carrier and an output planet carrier, the inner planet carrier and the output planet carrier are fixedly connected, and a plurality of planet gear shafts are provided between the inner planet carrier and the output planet carrier. The planet gear shaft is provided with a large planetary gear that meshes with the sun gear and a small planetary gear that meshes with the ring gear. The pitch circle diameter of the large planetary gear is larger than the pitch circle diameter of the small planetary gear.

2. The gear reducer according to claim 1, characterized in that: A clearance is provided between the internal planetary carrier and the output planetary carrier to accommodate the large planetary gear.

3. The gear reducer according to claim 1, characterized in that: The output planetary carrier is equipped with an output flange.

4. A joint actuator, characterized in that: The device includes a housing, within which a motor assembly and a gear reducer as described in any one of claims 1-3 are provided. The motor assembly includes a stator and a rotor sleeved within the stator. The rotor has a central through hole, and a transmission component that rotates synchronously with the rotor is provided within the central through hole. The transmission component is drively connected to the sun gear shaft. The gear ring is fixedly installed within the housing.

5. The joint actuator according to claim 4, characterized in that: The outer casing includes a housing and end caps mounted on the housing.

6. The joint actuator according to claim 5, characterized in that: The transmission component includes a transmission shaft, one end of which is provided with a first bearing between itself and the housing, and the second end of which is provided with a second bearing between itself and the internal planetary carrier. The transmission shaft rotates synchronously with the sun gear shaft.

7. The joint actuator according to claim 6, characterized in that: The drive shaft has a drive section in the middle that is connected to the rotor.

8. The joint actuator according to claim 5, characterized in that: A third bearing is provided between the end cover and the output planetary carrier, and the third bearing is a crossed roller bearing.

9. The joint actuator according to claim 4, characterized in that: The pitch circle diameter of the planetary gear is: Where: d2 is the pitch circle diameter of the planetary gear; d 2a d1 is the pitch circle diameter of the planetary gear; d2 is the pitch circle diameter of the sun gear; D is the inner diameter of the housing corresponding to the planetary gear position; Δ is the radial width of the clearance reserved between the planetary gear and the housing.

10. The joint actuator according to claim 9, characterized in that: The pitch circle diameter of the asteroid gear is: d3 = d4 - (d1 + d2) Where: d3 is the pitch circle diameter of the asteroid gear; d4 is the pitch circle diameter of the gear ring.

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