A two-speed planetary reducer and an electric servo system having the same

Abstract

The present application relates to a two-speed planetary reducer and an electric servo system having the two-speed planetary reducer, and relates to the technical field of servo systems. The two-speed planetary reducer in the present application includes a housing, in which a first-stage planetary reduction gear structure and a second-stage planetary reduction gear structure are arranged; the first-stage planetary reduction gear structure includes a hollow first-stage sun gear, and the second-stage planetary reduction gear structure includes a hollow second-stage sun gear. The first-stage sun gear and the second-stage sun gear are coaxially arranged, and a drive rod is slidably inserted in the first-stage sun gear and the second-stage sun gear; a first friction assembly is arranged between the drive rod and the first-stage sun gear, and a second friction assembly is arranged between the drive rod and the second-stage sun gear. When the drive member drives the drive rod to move axially, it can select either the first friction assembly or the second friction assembly to engage. The two-speed planetary reducer and electric servo system in the present application can quickly and accurately achieve switching between different speeds.

Description

Technical Field

[0001] The present application relates to the technical field of servo systems, and in particular to a two-speed planetary reducer and an electric servo system having the two-speed planetary reducer. Background Art

[0002] Planetary reducers, also known as servo planetary reducers or planetary gear reducers, are named for their transmission structure. Planetary reducers are widely used industrial products that reduce motor speed while increasing output torque. They are used as supporting components in industries such as lifting, excavation, transportation, and construction. Their main transmission structure consists of planetary gears, a sun gear, and an external ring gear. The single-stage reduction ratio of a planetary reducer ranges from a minimum of 3 to a maximum of 10, with common reduction ratios being 3, 4, 5, 7, and 10. Reducer stages typically include single, two, or three stages, but some models with larger reduction ratios can reach four stages.

[0003] At present, the planetary reducers in domestic small electric servo systems generally use single-speed transmission. A small number of electric servo systems that use variable speed structures usually require manual speed change. Speed change must be performed in a stationary state and gear alignment is required to achieve it, which will cause large gear clearance.

[0004] In the fields of drone servos, when adjusting the angle of the output shaft, it is necessary to adjust it as quickly as possible under no-load conditions and adjust it to a low gear when working under normal load. It is very inconvenient to use the structure in the above-mentioned related technologies. Summary of the Invention

[0005] In order to accurately and quickly achieve dual-speed adjustment of an electric servo system, the present application provides a dual-speed planetary reducer and an electric servo system having the dual-speed planetary reducer.

[0006] In the first aspect, the present application provides a two-speed planetary reducer adopting the following technical solution:

[0007] A two-speed planetary reducer comprises a housing, wherein a primary planetary reduction gear structure and a secondary planetary reduction gear structure are disposed within the housing, wherein an output end of the secondary planetary reduction gear structure is connected to an output gear structure; the primary planetary reduction gear structure comprises a hollow primary sun gear, and the secondary planetary reduction gear structure comprises a hollow secondary sun gear, wherein the primary sun gear and the secondary sun gear are coaxially disposed, and a drive rod is slidably inserted into the primary sun gear and the secondary sun gear;

[0008] One end of the drive rod is provided with a coupling for connecting to the output shaft of the motor, the drive rod and the coupling are axially sliding and circumferentially limited, and the other end of the drive rod is provided with a driving member for driving the drive rod to move within the primary sun gear and the secondary sun gear along the axis of the drive rod itself;

[0009] A first friction assembly is provided between the drive rod and the first-stage sun gear to enable the two to be engaged and disengaged, and a second friction assembly is provided between the drive rod and the second-stage sun gear to enable the two to be engaged and disengaged. When the drive member drives the drive rod to move axially, it can select either the first friction assembly or the second friction assembly to be engaged.

[0010] The planetary reducer in the present application is provided with at least two stages of reduction. By adopting the above-mentioned technical solution, the driving rod is circumferentially fixed to the output shaft of the motor, the output shaft of the motor can drive the driving rod to rotate circumferentially, and the driving member drives the driving rod to move axially. When the driving rod moves toward one side of the first-stage planetary reduction gear structure, the driving rod can engage the first friction component. At this time, the second friction component is separated, and the driving rod realizes torque transmission between the first friction component and the first-stage sun gear. The first-stage planetary reduction gear structure then transmits torque to the second-stage planetary reduction gear structure, realizing multi-stage reduction, thereby enabling the electric servo system to achieve low-speed and high-torque operation; when the driving rod moves toward one side of the second-stage planetary reduction gear structure, the driving rod can engage the second friction component. At this time, the first friction component is separated, and the driving rod realizes torque transmission between the second friction component and the second-stage sun gear. The second-stage planetary reduction gear structure transmits torque backward, and finally outputs the torque through the output gear structure. During this process, the first-stage planetary reduction gear structure idles and does not participate in the reduction function, thereby achieving high-speed and low-torque operation.

[0011] In this application, the two-speed planetary reducer outputs two different speeds efficiently and accurately through the driving member, driving rod, first friction assembly, and second friction assembly, namely, use under two working conditions: low speed and heavy load and high speed and light load; for example, when the position of the output shaft of the drone servo needs to be adjusted, the high speed and light load condition can be used, and the low speed and heavy load condition can be used during operation.

[0012] Optionally, the first friction assembly includes a first outer friction plate arranged in the first-stage sun gear through a spline hole and a first inner friction plate arranged on the drive rod and corresponding to the first outer friction plate; the second friction assembly includes a second outer friction plate arranged in the second-stage sun gear through a spline hole and a second inner friction plate arranged on the drive rod and corresponding to the second outer friction plate; when the drive rod moves axially, the first outer friction plate can be abutted against the first inner friction plate or the second outer friction plate can be abutted against the second inner friction plate.

[0013] By adopting the above technical solution, when the first outer friction plate and the first inner friction plate are in contact with each other, the first friction assembly can be formed into a combined state. At this time, the second outer friction plate and the second inner friction plate are separated, and the first-stage planetary reduction gear structure participates in the deceleration of the reducer, thereby enabling the electric servo system to achieve low-speed and high-torque operation; when the second outer friction plate and the second inner friction plate are in contact with each other, the second friction assembly can be formed into a combined state. At this time, the first outer friction plate and the first inner friction plate are separated, and the first-stage planetary reduction gear structure does not participate in the deceleration of the reducer, thereby enabling the electric servo system to achieve high-speed and low-torque output.

[0014] Optionally, there are several first outer friction plates that are arranged at intervals on the inner wall of the first-stage sun gear, and there are also several first inner friction plates that are arranged at intervals on the outer circumference of the drive rod, and several first outer friction plates and several first inner friction plates are arranged alternately in sequence; there are several second outer friction plates that are arranged at intervals on the inner wall of the second-stage sun gear, and there are also several second inner friction plates that are arranged at intervals on the outer circumference of the drive rod, and several second outer friction plates and several second inner friction plates are arranged alternately in sequence.

[0015] By adopting the above technical solution, several first outer friction plates and several first inner friction plates are arranged alternately in sequence, and several second outer friction plates and several second inner friction plates are arranged alternately in sequence; in this way, when the first friction assembly and the second friction assembly are in contact with each other, the torque transmission is more stable and reliable.

[0016] Optionally, the driving member is an electric push rod, the driving rod is a floating spline shaft, the driving rod is fixedly connected to the output shaft of the electric push rod or the driving rod is a part of the output shaft of the electric push rod; one end of the driving rod is slidably inserted in the coupling and the two are connected by a spline circumferential limit connection.

[0017] By adopting the above technical solution, the electric push rod drives the floating spline shaft to achieve speed regulation, which can switch the speed during movement, with accurate and reliable control and convenient remote control.

[0018] Optionally, the middle portion of the driving rod has an annular step, and a first compression spring and a first pressure plate are provided between one side of the annular step and the first friction assembly, a side surface of one side of the first pressure plate is in contact with a side surface of the first outer friction plate closest to the annular step, and two ends of the first compression spring respectively abut against the other side surface of the first pressure plate and the side surface of the annular step;

[0019] A second compression spring and a second pressure plate are provided between the other side of the annular step and the second friction assembly. One side surface of the second pressure plate is in contact with the side surface of the second outer friction plate closest to the annular step. Both ends of the second compression spring respectively rest against the other side surface of the second pressure plate and the side surface of the annular step.

[0020] By adopting the above technical solution, when the drive shaft moves, the first compression spring, the first pressure plate, the second compression spring and the second pressure plate are used to realize the abutment and combination of the first friction assembly and the second friction assembly, which is more stable and reliable.

[0021] Optionally, a three-stage planetary reduction gear structure is further provided between the two-stage planetary reduction gear structure and the output gear structure, and the three-stage planetary reduction gear structure includes a hollow three-stage sun gear, and the three-stage sun gear is coaxially arranged with the first-stage sun gear and the second-stage sun gear, and thrust needle roller bearings or dynamic friction plates are provided between the first-stage sun gear and the second-stage sun gear, and between the second-stage sun gear and the third-stage sun gear.

[0022] By adopting the above technical solution, the planetary reducer in this application can achieve three-stage reduction.

[0023] Optionally, a first-stage internal gear ring, a second-stage internal gear ring, and a third-stage internal gear ring are respectively arranged in intervals in the housing, and the first-stage planetary reduction gear structure further includes a first-stage planet carrier fixedly connected to the second-stage sun gear, and a plurality of first-stage planetary gears meshing with the first-stage internal gear ring are rotatably arranged in the first-stage planet carrier, and the first-stage sun gear is simultaneously meshed with the plurality of first-stage planetary gears;

[0024] The secondary planetary reduction gear structure further includes a secondary planet carrier fixedly connected to the third-stage sun gear, wherein a plurality of secondary planet gears meshing with the secondary internal gear ring are rotatably arranged in the secondary planet carrier, and the secondary sun gear is simultaneously meshed with the plurality of secondary planet gears;

[0025] The three-stage planetary reduction gear structure further includes a three-stage planet carrier, in which a plurality of three-stage planetary gears meshing with the three-stage internal gear ring are rotatably arranged, and the three-stage sun gear is simultaneously meshed with the plurality of the three-stage planetary gears;

[0026] One end of the three-stage planet carrier extends out of the housing, and the output gear structure includes an output pinion fixedly connected to the end of the three-stage planet carrier and an output gear meshing with the output pinion.

[0027] By adopting the above technical solution, when the motor is running, it drives the coupling to rotate, which in turn drives the floating spline shaft to rotate. When the first outer friction plate and the first inner friction plate are pressed against each other, the first sun gear rotates. At this time, there is a gap between the second outer friction plate and the second inner friction plate, separating them. The movement of the floating spline shaft does not drive the second sun gear to rotate. The first sun gear drives the first planet gears to rotate. The first planet gears are mounted on the first planet carrier and mesh with the fixed first internal gear, thereby driving the first planet carrier to rotate. The first planet carrier drives the second sun gear. The second sun gear drives the second planet gears mounted on the second planet carrier. The second planet gears mesh with the second internal gear, driving the second planet carrier to rotate. The second planet carrier drives the third sun gear. The third sun gear drives the third planet gears mounted on the third planet carrier, thereby driving the third planet carrier. The output pinion on the third planet carrier drives the output gear, thereby outputting the load. In this way, the motor's output torque is reduced by three planetary reduction gears and a first parallel shaft reduction gear, achieving low-speed, high-torque output.

[0028] Optionally, a bearing seat is provided at the center position of one end of the box body, the bearing seat faces the inner side of the box body, a support bearing is provided in the bearing seat, and one end of the central axis of the first-stage sun gear is inserted into the support bearing.

[0029] By adopting the above technical solution, the first-stage sun gear is stably and reliably supported at the end of the box, ensuring the stability and reliability of torque transmission, and the entire structure is compact and small in size.

[0030] Optionally, the other end of the box body is rotatably connected to the three-stage planetary carrier through a first bearing, the driving member is rotatably connected to the end of the three-stage planetary carrier through a second bearing, and the output shaft of the driving member passes through the three-stage planetary carrier and extends into the three-stage sun gear.

[0031] By adopting the above technical solution, the drive component and the motor are respectively arranged at both ends of the box, and the entire structure is compact, which greatly reduces the volume of the entire electric servo system. In addition, the gears inside the two-speed planetary reducer are located in a closed space, reducing interference from foreign matter such as dust, and the torque transmission is more stable.

[0032] In a second aspect, the present application provides an electric servo system with a dual-speed planetary reducer adopting the following technical solution:

[0033] An electric servo system with a two-speed planetary reducer, the electric servo system having the two-speed planetary reducer.

[0034] By adopting the above technical solution, the electric servo system in this application can be used in fields such as drone servos. When adjusting the angle of the output shaft of the drone servo, it can be adjusted to the position as quickly as possible under no-load conditions and adjusted to a low speed gear when working under normal load. It can also be wirelessly controlled, and the movement is precise and reliable.

[0035] In summary, this application includes at least one of the following beneficial technical effects:

[0036] 1. The two-speed planetary reducer in this application efficiently and accurately realizes the output of two different speeds of the two-speed planetary reducer through the driving member, the driving rod, the first friction assembly, and the second friction assembly, namely, the use under two working conditions: low speed and heavy load and high speed and light load.

[0037] 2. In this application, the speed is adjusted by driving the floating spline shaft with an electric push rod, the speed can be switched during movement, and remote control is conveniently implemented.

[0038] 3. The friction transmission torque of the first friction assembly and the second friction assembly is adopted in this application, which does not require the gear alignment requirement during the speed gear switching process and is not prone to damage to the gears. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic cross-sectional view of the dual-speed planetary reducer in this embodiment.

[0040] Figure 2 It is a partial cross-sectional structural schematic diagram of the two-speed planetary reducer in this embodiment.

[0041] Figure 3 Schematic diagram of the assembly structure of the drive rod, the first friction assembly and the second friction assembly in this embodiment.

[0042] In the figure, 1. housing; 2. first-stage planetary reduction gear structure; 21. first-stage sun gear; 22. first-stage planet carrier; 23. first-stage planetary gear; 24. first-stage internal gear; 3. second-stage planetary reduction gear structure; 31. second-stage sun gear; 32. second-stage planet carrier; 33. second-stage planetary gear; 34. second-stage internal gear; 4. third-stage planetary reduction gear structure; 41. third-stage sun gear; 42. third-stage planet carrier; 43. third-stage planetary gear; 44. third-stage internal gear; 5. output gear structure; 51. output gear Output small gear; 52, output large gear; 6, drive rod; 61, annular step; 7, coupling; 8, drive member; 9, first friction assembly; 91, first outer friction plate; 92, first inner friction plate; 10, second friction assembly; 101, second outer friction plate; 102, second inner friction plate; 11, first compression spring; 12, first pressure plate; 13, second compression spring; 14, second pressure plate; 15, dynamic friction plate; 16, bearing seat; 17, support bearing; 18, first bearing; 19, second bearing. DETAILED DESCRIPTION

[0043] The following is combined with Figure 1 To the attached Figure 3 This application is described in further detail.

[0044] Reference Figure 1 The two-speed planetary reducer in this application includes a housing 1, one end of the housing 1 is used to install the motor, and the other end is used to install the driving member 8, which is an electric push rod.

[0045] Reference Figure 1 In the box body 1, a first-stage planetary reduction gear structure 2, a second-stage planetary reduction gear structure 3 and a third-stage planetary reduction gear structure 4 are sequentially arranged from one end where the motor is installed to one end where the driving member 8 is installed.

[0046] Reference Figure 1 , the first-stage planetary reduction gear structure 2 includes a first-stage sun gear 21, a first-stage planet carrier 22, a first-stage inner ring gear 24 and a plurality of first-stage planetary gears 23; the second-stage planetary reduction gear structure 3 includes a second-stage sun gear 31, a second-stage planet carrier 32, a second-stage inner ring gear 34 and a plurality of second-stage planetary gears 33; the third-stage planetary reduction gear structure 4 includes a third-stage sun gear 41, a third-stage planet carrier 42, a third-stage inner ring gear 44 and a plurality of third-stage planetary gears 43; the first-stage inner ring gear 24, the second-stage inner ring gear 34 and the third-stage inner ring gear 44 are arranged side by side in the housing 1; the first-stage planet carrier 22 is fixedly connected to the second-stage sun gear 31, and a plurality of first-stage planetary gears 23 are rotatably arranged in the first-stage planet carrier 22 and are evenly spaced along the circumference of the first-stage planet carrier 22. There can be three first-stage planetary gears 23, and the first-stage planetary gears The wheels 23 are all meshed with the primary internal gear ring 24, and the primary sun gear 21 is also meshed with several primary planetary gears 23; the secondary planet carrier 32 is fixedly connected to the tertiary sun gear 41, and several secondary planetary gears 33 are rotatably arranged in the secondary planet carrier 32 and are evenly spaced along the circumference of the secondary planet carrier 32. There can be three secondary planetary gears 33, and the secondary planetary gears 33 are all meshed with the secondary internal gear ring 34, and the secondary sun gear 31 is also meshed with several secondary planetary gears 33; several tertiary planetary gears 43 are rotatably arranged in the tertiary planet carrier 42 and are evenly spaced along the circumference of the tertiary planet carrier 42. There can be three tertiary planetary gears 43, and the tertiary planetary gears 43 are all meshed with the tertiary internal gear ring 44, and the tertiary sun gear 41 is also meshed with several tertiary planetary gears 43. One end of the three-stage planetary carrier 42 extends out of the box body 1, and an output gear structure 5 is provided at the end of the three-stage planetary carrier 42. The output gear structure 5 includes an output pinion 51 fixedly connected to the end of the three-stage planetary carrier 42 and an output gear 52 meshing with the output pinion 51.

[0047] Reference Figure 1 and Figure 2 The first-stage sun gear 21, the second-stage sun gear 31 and the third-stage sun gear 41 are all hollow structures. The first-stage sun gear 21, the second-stage sun gear 31 and the third-stage sun gear 41 are coaxially arranged. Thrust needle roller bearings or dynamic friction plates 15 are arranged between the first-stage sun gear 21 and the second-stage sun gear 31, and between the second-stage sun gear 31 and the third-stage sun gear 41. A drive rod 6 is slidably inserted in the first-stage sun gear 21 and the second-stage sun gear 31; one end of the drive rod 6 is provided with a coupling 7 for connecting to the output shaft of the motor, and the drive rod 6 and the coupling 7 are axially sliding and circumferentially limited. The other end of the drive rod 6 is connected to the output shaft of the drive member 8. The drive rod 6 is a floating spline shaft, and the drive rod 6 is fixed on the output shaft of the electric push rod or the drive rod 6 is part of the output shaft of the electric push rod; one end of the drive rod 6 is slidably inserted in the coupling 7 and the two are connected circumferentially by a spline; the drive member 8 drives the drive rod 6 to move along the axis of the drive rod 6 itself in the first-stage sun gear 21 and the second-stage sun gear 31.

[0048] Reference Figure 2 and Figure 3 A first friction assembly 9 is disposed between the drive rod 6 and the primary sun gear 21, enabling them to engage and disengage. A second friction assembly 10 is disposed between the drive rod 6 and the secondary sun gear 31, enabling them to engage and disengage. When the drive member 8 drives the drive rod 6 to move axially, either the first friction assembly 9 or the second friction assembly 10 can be selectively engaged. The first friction assembly 9 comprises a first outer friction plate 91 disposed through a spline hole in the primary sun gear 21, and a first inner friction plate 92 disposed on the drive rod 6 and corresponding to the first outer friction plate 91. The second friction assembly 10 comprises a second outer friction plate 101 disposed through a spline hole in the secondary sun gear 31, and a second inner friction plate 102 disposed on the drive rod 6 and corresponding to the second outer friction plate 101. When the drive rod 6 moves axially, either the first outer friction plate 91 abuts against the first inner friction plate 92, or the second outer friction plate 101 abuts against the second inner friction plate 102. When the first outer friction plate 91 and the first inner friction plate 92 are pressed against each other, the first friction assembly 9 can be formed into a combined state. At this time, the second outer friction plate 101 and the second inner friction plate 102 are separated, and the first-stage planetary reduction gear structure 2 participates in the deceleration of the reducer, thereby enabling the electric servo system to achieve low-speed and high-torque operation; when the second outer friction plate 101 and the second inner friction plate 102 are pressed against each other, the second friction assembly 10 can be formed into a combined state. At this time, the first outer friction plate 91 and the first inner friction plate 92 are separated, and the first-stage planetary reduction gear structure 2 does not participate in the deceleration of the reducer, thereby enabling the electric servo system to achieve high-speed and low-torque output.

[0049] Reference Figure 3There are multiple first outer friction plates 91 spaced apart on the inner wall of the primary sun gear 21, and multiple first inner friction plates 92 spaced apart on the outer circumference of the drive rod 6. These multiple first outer friction plates 91 and multiple first inner friction plates 92 are arranged alternately. There are multiple second outer friction plates 101 spaced apart on the inner wall of the secondary sun gear 31, and multiple second inner friction plates 102 spaced apart on the outer circumference of the drive rod 6. These multiple second outer friction plates 101 and multiple second inner friction plates 102 are arranged alternately. By arranging multiple first outer friction plates 91 and multiple first inner friction plates 92 alternately, and multiple second outer friction plates 101 and multiple second inner friction plates 102 alternately, when the first friction assembly 9 and the second friction assembly 10 are in contact with each other, torque transmission is more stable and reliable.

[0050] Reference Figure 3 The drive rod 6 has an annular step 61 in the middle. A first compression spring 11 and a first pressure plate 12 are disposed between one side of the annular step 61 and the first friction assembly 9. One side of the first pressure plate 12 abuts against the side of the first outer friction plate 91 closest to the annular step 61, and the two ends of the first compression spring 11 abut against the other side of the first pressure plate 12 and the side of the annular step 61. A second compression spring 13 and a second pressure plate 14 are disposed between the other side of the annular step 61 and the second friction assembly 10. One side of the second pressure plate 14 abuts against the side of the second outer friction plate 101 closest to the annular step 61, and the two ends of the second compression spring 13 abut against the other side of the second pressure plate 14 and the side of the annular step 61. When the drive shaft moves, the first compression spring 11, first pressure plate 12, second compression spring 13, and second pressure plate 14 ensure a more stable and reliable engagement between the first and second friction assemblies 9 and 10.

[0051] Reference Figure 1 As shown, a bearing seat 16 is provided at the center of one end of the housing 1. The bearing seat 16 faces the inner side of the housing 1. A support bearing 17 is provided in the bearing seat 16. One end of the central axis of the first-stage sun gear 21 is inserted into the support bearing 17. The first-stage sun gear 21 is stably and reliably supported at the end of the housing 1, ensuring the stability and reliability of torque transmission. The entire structure is compact and small in size. The other end of the housing 1 is rotatably connected to the third-stage planetary carrier 42 via a first bearing 18. The driving member 8 is rotatably connected to the end of the third-stage planetary carrier 42 via a second bearing 19. The output shaft of the driving member 8 passes through the third-stage planetary carrier 42 and extends into the third-stage sun gear 41. The driving member 8 and the motor are respectively provided at both ends of the housing 1. The entire structure is compact, which greatly reduces the volume of the entire electric servo system. The gears inside the two-speed planetary reducer are located in a closed space, reducing interference from foreign matter such as dust, and making torque transmission more stable.

[0052] The implementation principle is as follows: the planetary reducer in the present application is set to three-stage reduction, the drive rod 6 is circumferentially fixed to the output shaft of the motor, the output shaft of the motor can drive the drive rod 6 to rotate circumferentially, and the drive member 8 drives the drive rod 6 to move axially. When the drive rod 6 moves toward the side of the first-stage planetary reduction gear structure 2, the drive rod 6 can engage the first friction component 9. At this time, the second friction component 10 is separated. The drive rod 6 realizes torque transmission between the first friction component 9 and the first-stage sun gear 21. The first-stage planetary reduction gear structure 2 then transmits torque to the second-stage planetary reduction gear structure 3, realizing multi-stage reduction, thereby enabling the electric servo system to achieve low-speed and high-torque operation; when the drive rod 6 moves toward the side of the second-stage planetary reduction gear structure 3, the drive rod 6 can engage the second friction component 10. At this time, the first friction component 9 is separated. The drive rod 6 realizes torque transmission between the second friction component 10 and the second-stage sun gear 31. The second-stage planetary reduction gear structure 3 transmits torque backward and finally outputs the torque through the output gear structure 5. During this process, the first-stage planetary reduction gear structure 2 is idling and does not participate in the reduction function, achieving high-speed and low-torque operation.

[0053] In this application, the drive element 8, drive rod 6, first friction assembly 9, and second friction assembly 10 efficiently and accurately achieve two different speeds for the dual-speed planetary reducer, namely, low-speed heavy-load and high-speed light-load. For example, when adjusting the output shaft position of a drone servo, the high-speed light-load condition can be used, while the low-speed heavy-load condition can be used during operation. The electric push rod drives the floating spline shaft to achieve speed regulation, allowing speed switching during movement, precise and reliable control, and convenient remote control.

[0054] When the motor is running, it drives the coupling 7 to rotate, and then drives the floating spline shaft to rotate. When the first outer friction plate 91 and the first inner friction plate 92 are pressed against each other, the first sun gear 21 is driven to rotate. At this time, there is a gap between the second outer friction plate 101 and the second inner friction plate 102, and the two are separated. The movement of the floating spline shaft will not drive the secondary sun gear 31 to rotate. The first sun gear 21 drives the first planetary gear to rotate. The first planetary gear is installed on the first planetary carrier 22 and meshes with the fixed first inner ring gear 24, thereby driving the first planetary carrier 22 to rotate. The first planetary carrier 22 drives the second sun gear 31 to rotate; the second sun gear 31 drives the second planetary gear installed on the second planetary carrier 32 to rotate, and the second planetary gear and the second inner ring gear 34 mesh, driving the second planetary carrier 32 to rotate. The second planetary carrier 32 drives the third sun gear 41 to rotate; the third sun gear 41 drives the third planetary gear installed on the third planetary carrier 42 to rotate, driving the third planetary carrier 42 to rotate. The output pinion 51 on the three-stage planetary carrier 42 drives the output gear 52 to rotate, thereby outputting the load. In this way, the motor output torque is reduced by three stages of planetary reduction and one stage of parallel shaft reduction, achieving low-speed and high-torque output.

[0055] This embodiment also provides an electric servo system with a two-speed planetary reducer. The electric servo system can be used in fields such as drone servos. When adjusting the angle of the drone servo output shaft, it meets the requirements of quickly adjusting to the desired position under no-load conditions and adjusting to a low speed gear under normal load conditions. Furthermore, the system can be wirelessly controlled, ensuring precise and reliable operation.

[0056] The examples of this specific embodiment are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, any equivalent changes made based on the structure, shape, and principle of this application should be included in the scope of protection of this application.

Claims

1. A two-speed planetary reducer, comprising a housing (1), characterized in that: A first-stage planetary reduction gear structure (2) and a second-stage planetary reduction gear structure (3) are provided in the housing (1); an output end of the second-stage planetary reduction gear structure (3) is connected to an output gear structure (5); the first-stage planetary reduction gear structure (2) includes a hollow first-stage sun gear (21); the second-stage planetary reduction gear structure (3) includes a hollow second-stage sun gear (31); the first-stage sun gear (21) and the second-stage sun gear (31) are coaxially arranged, and a driving rod (6) is slidably inserted in the first-stage sun gear (21) and the second-stage sun gear (31); One end of the driving rod (6) is provided with a coupling (7) for connecting to the output shaft of the motor, the driving rod (6) and the coupling (7) are axially sliding and circumferentially limited, and the other end of the driving rod (6) is provided with a driving member (8) for driving the driving rod (6) to move along the axis of the driving rod (6) itself within the primary sun gear (21) and the secondary sun gear (31); A first friction assembly (9) is provided between the driving rod (6) and the primary sun gear (21) to enable the two to be engaged and disengaged, and a second friction assembly (10) is provided between the driving rod (6) and the secondary sun gear (31) to enable the two to be engaged and disengaged. When the driving member (8) drives the driving rod (6) to move axially, it can select either the first friction assembly (9) to be engaged or the second friction assembly (10) to be engaged.

2. The dual-speed planetary reducer according to claim 1, characterized in that: The first friction assembly (9) includes a first outer friction plate (91) arranged in the first-stage sun gear (21) through a spline hole and a first inner friction plate (92) arranged on the drive rod (6) and corresponding to the first outer friction plate (91); the second friction assembly (10) includes a second outer friction plate (101) arranged in the second-stage sun gear (31) through a spline hole and a second inner friction plate (102) arranged on the drive rod (6) and corresponding to the second outer friction plate (101); when the drive rod (6) moves axially, the first outer friction plate (91) can be in contact with the first inner friction plate (92) or the second outer friction plate (101) can be in contact with the second inner friction plate (102).

3. The dual-speed planetary reducer according to claim 2, characterized in that: There are a plurality of first outer friction plates (91) arranged at intervals on the inner wall of the first-stage sun gear (21), and there are a plurality of first inner friction plates (92) arranged at intervals on the outer peripheral surface of the drive rod (6), and a plurality of first outer friction plates (91) and a plurality of first inner friction plates (92) are arranged alternately in sequence; there are a plurality of second outer friction plates (101) arranged at intervals on the inner wall of the second-stage sun gear (31), and there are a plurality of second inner friction plates (102) arranged at intervals on the outer peripheral surface of the drive rod (6), and a plurality of second outer friction plates (101) and a plurality of second inner friction plates (102) are arranged alternately in sequence.

4. The dual-speed planetary reducer according to claim 1, 2 or 3, characterized in that: The driving member (8) is an electric push rod, the driving rod (6) is a floating spline shaft, the driving rod (6) is fixedly connected to the output shaft of the electric push rod or the driving rod (6) is a part of the output shaft of the electric push rod; one end of the driving rod (6) is slidably inserted into the coupling (7) and the two are connected by a spline circumferential limit connection.

5. The dual-speed planetary reducer according to claim 3, characterized in that: The middle portion of the driving rod (6) has an annular step (61), and a first compression spring (11) and a first pressure plate (12) are provided between one side of the annular step (61) and the first friction assembly (9), and the side surface of one side of the first pressure plate (12) is in contact with the side surface of the first outer friction plate (91) closest to the annular step (61), and the two ends of the first compression spring (11) respectively abut against the other side surface of the first pressure plate (12) and the side surface of the annular step (61); A second compression spring (13) and a second pressure plate (14) are provided between the other side of the annular step (61) and the second friction assembly (10), one side surface of the second pressure plate (14) is in contact with the side surface of the second outer friction plate (101) closest to the annular step (61), and both ends of the second compression spring (13) are respectively against the other side surface of the second pressure plate (14) and the side surface of the annular step (61).

6. The dual-speed planetary reducer according to claim 3, characterized in that: A three-stage planetary reduction gear structure (4) is further provided between the two-stage planetary reduction gear structure (3) and the output gear structure (5). The three-stage planetary reduction gear structure (4) includes a hollow three-stage sun gear (41). The three-stage sun gear (41) is coaxially arranged with the one-stage sun gear (21) and the two-stage sun gear (31). Thrust needle roller bearings or dynamic friction plates (15) are provided between the one-stage sun gear (21) and the two-stage sun gear (31), and between the two-stage sun gear (31) and the three-stage sun gear (41).

7. The two-speed planetary reducer according to claim 6, characterized in that: A first-stage inner gear ring (24), a second-stage inner gear ring (34), and a third-stage inner gear ring (44) are arranged in the housing (1) at intervals, and the first-stage planetary reduction gear structure (2) further comprises a first-stage planet carrier (22) fixedly connected to the second-stage sun gear (31), and a plurality of first-stage planetary gears (23) meshing with the first-stage inner gear ring (24) are rotatably arranged in the first-stage planet carrier (22), and the first-stage sun gear (21) is simultaneously meshed with the plurality of first-stage planetary gears (23); The secondary planetary reduction gear structure (3) further comprises a secondary planet carrier (32) fixedly connected to the third-stage sun gear (41), wherein a plurality of secondary planetary gears (33) meshing with the secondary inner gear ring (34) are rotatably arranged in the secondary planet carrier (32), and the secondary sun gear (31) is simultaneously meshed with the plurality of secondary planetary gears (33); The three-stage planetary reduction gear structure (4) further includes a three-stage planetary carrier (42), wherein a plurality of three-stage planetary gears (43) meshing with the three-stage inner gear ring (44) are rotatably arranged in the three-stage planetary carrier (42), and the three-stage sun gear (41) is simultaneously meshed with the plurality of the three-stage planetary gears (43); One end of the three-stage planetary carrier (42) extends out of the housing (1), and the output gear structure (5) comprises an output pinion (51) fixedly connected to the end of the three-stage planetary carrier (42) and an output gear (52) meshing with the output pinion (51).

8. The two-speed planetary reducer according to claim 7, characterized in that: A bearing seat (16) is provided at the center position of one end of the housing (1), the bearing seat (16) faces the inner side of the housing (1), a support bearing (17) is provided in the bearing seat (16), and one end of the central axis of the first-stage sun gear (21) is inserted into the support bearing (17).

9. The two-speed planetary reducer according to claim 8, characterized in that: The other end of the housing (1) is rotatably connected to the three-stage planetary carrier (42) via a first bearing (18), the driving member (8) is rotatably connected to the end of the three-stage planetary carrier (42) via a second bearing (19), and the output shaft of the driving member (8) passes through the three-stage planetary carrier (42) and extends into the three-stage sun gear (41).

10. An electric servo system with a dual-speed planetary reducer, characterized in that: The electric servo system has the two-speed planetary reducer according to any one of claims 1 to 9.

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