Two-stage gear reduction mechanism with characteristic of symmetrical output at two ends

Abstract

Disclosed in the present invention is a two-stage gear reduction mechanism with the characteristic of symmetrical output at two ends, the two-stage gear reduction mechanism comprising an electric motor, planetary carriers, planetary gears and a housing, wherein a first-stage driving gear is provided on an output shaft of the electric motor; sun gears and a first-stage large gear are coaxially provided between the planetary carriers; an idler gear meshes and is connected between the first-stage driving gear and the first-stage large gear; the sun gears are respectively located on two sides of the first-stage large gear, and sun gear shafts are rotationally connected to the centers of the planetary carriers; three groups of planetary gears are symmetrically and coaxially provided on two sides of the first-stage large gear, and the planetary gears are all rotationally connected to the planetary carriers; a ring gear is fixedly provided in the housing; each planetary gear meshes with both the ring gear and the sun gears; and an output stud is fixedly provided on each planetary carrier. The reduction mechanism of the present invention can realize multi-stage speed reduction in a limited space, and uses a modular shafting layout, such that a planetary gear set is convenient to assemble and disassemble, and the power load is effectively balanced.

Description

Two-stage gear reduction mechanism with symmetrical output at both ends Technical Field

[0001] This invention relates to the field of flapping-wing aircraft drive technology, and in particular to a two-stage gear reduction mechanism with symmetrical output at both ends. Background Technology

[0002] Ornithoptering aircraft generate lift and thrust by mimicking the reciprocating flapping of birds' or insects' wings. They possess advantages such as strong biomimicry, high maneuverability, and good stealth, making them promising for applications in reconnaissance, surveillance, and education. Currently, ornithopter transmission systems face the dual challenges of miniaturization and efficiency. Achieving high transmission ratios and low-loss power transmission within limited fuselage space is a core research direction in the industry. In ornithopter transmission systems, planetary gear trains, with their small radial dimensions and smooth power transmission, have become an ideal choice for achieving high transmission ratios. Currently, planetary gear trains used in ornithopters are often combined with cylindrical gears and other transmission structures to form composite transmission schemes, balancing deceleration effects with space constraints. Technical issues

[0003] However, existing planetary gear systems used in ornithopters still have shortcomings: on the one hand, the output mode of a single planetary gear system is difficult to meet the symmetrical power output requirements of ornithopters at both ends, requiring the addition of a power distribution mechanism, which leads to structural complexity; on the other hand, some planetary gear systems adopt an integral housing and fixed shaft design, which makes it inconvenient to disassemble and maintain the internal gear set, and is prone to vibration due to axial force imbalance during high-speed operation, affecting transmission stability and component life.

[0004] For example, the flapping wing mechanism based on incomplete gear transmission disclosed in invention patent CN115230959B converts the motor's rotational motion into the reciprocating flapping of the flapping wing rod through a three-stage transmission architecture of "motor output shaft gear + reduction gear structure + multiple sets of incomplete gears," thereby improving the synchronization and uniformity of flapping wing speed. However, the vertical arrangement of the motor and the integral gearbox result in a high space occupancy rate (over 80mm axial length), low meshing overlap of the spur gears, leading to significant high-speed vibration and noise. Furthermore, the integral housing requires the removal of more than 12 bolts for disassembly and assembly, making maintenance and adjustment inconvenient. Therefore, there is an urgent need for a reduction mechanism that can achieve multi-stage reduction within a limited space, uses a modular shaft layout, facilitates the disassembly and assembly of the planetary gear set, and effectively balances the power load. Technical solutions

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and to provide a reduction mechanism that can achieve multi-stage reduction in a limited space, uses a modular shaft layout, facilitates the disassembly and assembly of planetary gear sets, and effectively balances the power load.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] A two-stage gear reduction mechanism with symmetrical output at both ends includes a motor, a planetary carrier, planetary gears, and a housing. A primary driving gear is mounted on the output shaft of the motor. A sun gear and a primary large gear are coaxially mounted between the planetary carriers. An idler gear meshes between the primary driving gear and the primary large gear. The sun gears are located on both sides of the primary large gear, and their shafts are rotatably connected to the center of the planetary carrier. Three sets of planetary gears are symmetrically and coaxially mounted on both sides of the primary large gear. Each planetary gear is rotatably connected to the planetary carrier. A gear ring is fixedly mounted inside the housing, and each planetary gear simultaneously meshes with both the gear ring and the sun gear. An output stud is fixedly mounted on the planetary carrier.

[0008] Furthermore, the primary drive gear is fixedly connected to the output shaft of the motor via a 3mm set screw, and both the primary large gear and the sun gear are keyed to the sun gear shaft.

[0009] Furthermore, the planetary gear is connected to the planetary carrier via PTFE pins and washers.

[0010] Furthermore, the output shaft of the motor is connected to the mounting bracket via a flange bearing, and the idler shaft, sun gear shaft, and outer edge of the planet carrier of the idler gear are all connected to the housing via flange bearings.

[0011] Furthermore, the outer casing has a symmetrical split structure, and the motor mounting bracket is connected to the outer casing by fixing bolts.

[0012] Furthermore, both the primary drive gear and the primary large gear are herringbone gears, and the planetary gears are helical gears. Beneficial effects

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] This invention employs a modular layout, reducing the space occupied by the transmission system and improving its compatibility with ornithopter fuselages. It utilizes a composite reduction scheme of "first-stage external meshing gear + second-stage planetary gear" to meet the requirements of high transmission ratio and high efficiency. Through a three-set mirrored planetary gear system design, symmetrical output is achieved at both ends with the planetary carrier as the output end. Simultaneously, mirrored helical gears are used to cancel out axial forces, improving transmission accuracy and utilizing axial forces for component positioning. Attached Figure Description

[0015] Figure 1 is a schematic diagram of the structure of the present invention;

[0016] Figure 2 is a diagram of the internal structure of the present invention;

[0017] Figure 3 is a structural diagram of the present invention with the outer shell removed.

[0018] Figure label:

[0019] 1-Motor, 2-First stage drive gear, 3-Idler gear, 4-First stage large gear, 5-Sun gear, 6-Sun gear shaft, 7-Planet gear, 8-Ring gear, 9-Planet carrier, 10-Output stud, 11-Flange bearing, 12-Housing, 13-Reinforcing member, 14-Mounting bracket, 15-Idler gear shaft. Embodiments of the present invention

[0020] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] As shown in Figures 1 to 3, a two-stage gear reduction mechanism with symmetrical output at both ends includes a motor 1, a planetary carrier 9, planetary gears 7, and a housing 12. A primary drive gear 2 is mounted on the output shaft of the motor 1. A sun gear 5 and a primary large gear 4 are coaxially mounted between the planetary carriers 9. An idler gear 3 meshes between the primary drive gear 2 and the primary large gear 4. The sun gears 5 are located on both sides of the primary large gear 4, and the sun gear shaft 6 is rotatably connected to the center of the planetary carrier 9. Three sets of planetary gears 7 are symmetrically and coaxially mounted on both sides of the primary large gear 4. Each planetary gear 7 is rotatably connected to the planetary carrier 9. A gear ring 8 is fixedly mounted inside the housing 12. Each planetary gear 7 meshes with both the gear ring 8 and the sun gear 5. An output stud 10 is fixedly mounted on the planetary carrier 9.

[0022] The primary drive gear 2 is fixedly connected to the output shaft of the motor 1 via a 3mm set screw, and the primary large gear 4 and the sun gear 5 are both keyed to the sun gear shaft 6 to realize the synchronous transmission of power to the planetary gears 7 on the left and right sides.

[0023] The planetary gear 7 is connected to the planetary carrier 9 by a pin and a washer made of polytetrafluoroethylene, which not only makes the structure lightweight and easy to install, but also effectively reduces friction and wear and extends service life.

[0024] The output shaft of the motor 1 is connected to the mounting bracket 14 via a flange bearing 11. The outer edges of the idler shaft 15, sun gear shaft 6, and planetary carrier 9 of the idler gear 3 are all connected to the housing 12 via flange bearings 11. The flange bearings 11 serve to provide support and lubrication, ensuring stable operation of the shaft system.

[0025] The outer casing 12 has a symmetrical split structure, and the mounting bracket of the motor 1 is connected to the outer casing 12 by fixing bolts. The split outer casing 12 facilitates disassembly and replacement of internal components, thereby supporting the rapid replacement of motors of different specifications, as well as the rapid replacement and adjustment of the planetary gear 7 and the transmission ratio, realizing the modular integration and iterative upgrade of the system.

[0026] The primary drive gear 2 and the primary large gear 4 are both herringbone gears, which have good centering and transmission smoothness. The planetary gear 7 is a helical gear, which can effectively counteract axial force and make reasonable use of axial force to achieve part positioning and improve operational stability. Moreover, all transmission shafts are arranged in parallel to avoid the use of bevel gears, so as to maintain a compact structure and high transmission efficiency.

[0027] This patent describes the driving method of the linkage mechanism in the flapping-wing aircraft as follows: As shown in Figure 3, the output shaft of motor 1 drives the primary drive gear 2, which in turn drives the idler gear 3. The idler gear 3 drives the primary large gear 4 for deceleration. The primary large gear 4 transmits power to the sun gear 5 through the sun gear shaft 6. The sun gear 5 drives three sets of planetary gears 7 to rotate within a fixed gear ring 8, and then revolve around the planetary carrier 9, driving the planetary carrier 9 to decelerate and output power. Finally, the planetary carrier 9 transmits the amplified torque to the flapping-wing linkage mechanism through the output stud 10, realizing the reciprocating flapping of the wing. The three sets of planetary gears 7 are arranged symmetrically in a mirror image, which helps to counteract axial forces and uses axial forces to achieve the positioning of each component.

[0028] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A two-stage gear reduction mechanism with symmetrical output at both ends, comprising a motor (1), a planetary carrier (9), planetary gears (7), and a housing (12), characterized in that: The output shaft of the motor (1) is provided with a first-stage driving gear (2). The planet carrier (9) is coaxially provided with a sun gear (5) and a first-stage large gear (4). The first-stage driving gear (2) and the first-stage large gear (4) are meshed with an idler gear (3). The sun gear (5) is located on both sides of the first-stage large gear (4) and the sun gear shaft (6) is rotatably connected to the center of the planet carrier (9). The planet gears (7) are symmetrically and coaxially arranged in three sets on both sides of the first-stage large gear (4). Each planet gear (7) is rotatably connected to the planet carrier (9). The outer shell (12) is fixedly provided with a gear ring (8). Each planet gear (7) meshes with the gear ring (8) and the sun gear (5) at the same time. The planet carrier (9) is fixedly provided with an output stud (10).

2. The two-stage gear reduction mechanism with symmetrical output at both ends as described in claim 1, characterized in that: The primary drive gear (2) is fixedly connected to the output shaft of the motor (1) via a 3mm set screw, and the primary large gear (4) and the sun gear (5) are both keyed to the sun gear shaft (6).

3. The two-stage gear reduction mechanism with symmetrical output at both ends as described in claim 1, characterized in that: The planetary gear (7) is connected to the planet carrier (9) by a PTFE pin and a washer.

4. The two-stage gear reduction mechanism with symmetrical output at both ends as described in claim 1, characterized in that: The output shaft of the motor (1) is connected to the mounting bracket (14) via a flange bearing (11), and the outer edges of the idler shaft (15), sun shaft (6), and planet carrier (9) of the idler (3) are all connected to the outer casing (12) via flange bearings (11).

5. The two-stage gear reduction mechanism with symmetrical output at both ends as described in claim 1, characterized in that: The outer shell (12) is a symmetrical split structure, and the mounting bracket (14) of the motor (1) is connected to the outer shell (12) by fixing bolts.

6. The two-stage gear reduction mechanism with symmetrical output at both ends as described in claim 1, characterized in that: Both the primary drive gear (2) and the primary large gear (4) are herringbone gears, and the planetary gear (7) is a helical gear.

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