A turning angle harmonic reducer of a drone rudder

Abstract

The utility model provides an angle harmonic reducer of unmanned aerial vehicle rudder, belongs to unmanned aerial vehicle technical field. It solved the existing angle harmonic reducer is not conducive to unmanned aerial vehicle lightweight design etc. Angle harmonic reducer of unmanned aerial vehicle rudder, including casing, input shaft and output shaft, is provided with wave generator in the casing, the outer circumferential side of wave generator is equipped with flexible bearing, is equipped with flexible gear on flexible bearing, the outer circumferential side of flexible gear is equipped with rigid wheel, the casing includes first shell and second shell, the outer circumferential surface of rigid wheel middle part has protruding clamping portion, and clamping portion clamps and fixes between first shell and second shell, and the both ends of rigid wheel are inserted into first shell and second shell respectively, and the outer circumferential surface of rigid wheel both ends respectively with the inner wall surface of first shell and the inner wall surface of second shell is close to, and the output of flexible gear is fixedly connected on output shaft through bolt. This angle harmonic reducer can reduce weight while guaranteeing normal work, thereby is favorable to the lightweight design of unmanned aerial vehicle.

Description

Technical Field

[0001] This utility model belongs to the field of unmanned aerial vehicle (UAV) technology and relates to an angle harmonic reducer for a UAV servo motor. Background Technology

[0002] A servo motor is an actuator that controls the rotation of the control surfaces (rudder surfaces) of an aircraft in an autopilot. Currently, UAV servos are driven by motors, with a reducer connected to the output shaft of the motor.

[0003] For example, Chinese patent literature discloses a right-angle harmonic reducer (publication number CN110145586A), which includes a housing, a harmonic generator, a power input shaft, and an output support shaft. The axial direction of the power input shaft is at an angle to the axial direction of the harmonic generator. The harmonic generator and the power input shaft are connected via an intermediate transmission mechanism. The intermediate transmission mechanism includes a reversing gear, which is connected to the harmonic generator, and their axes are collinear. The harmonic generator and the reversing gear are integrally formed. The output support shaft passes through the harmonic generator, which is supported on the output support shaft by bearings. The output support shaft is connected to a flexible gear via an output rigid wheel. The flexible gear also meshes with a rigid gear, which is housed within the housing and is integrally formed with the housing. To ensure the wear resistance and high strength of rigid gears, alloy structural steel is often used for rigid gears. When the rigid gears are integrally formed with the housing, the housing is also made of alloy structural steel. As a result, the weight of this orthogonal shaft harmonic reducer is too heavy when used in the servo of a drone, which is not conducive to the lightweight design of the drone. Utility Model Content

[0004] The purpose of this invention is to address the aforementioned problems in the existing technology by proposing an angle harmonic reducer for UAV servos, thus solving the technical problem that existing angle harmonic reducers are not conducive to the lightweight design of UAVs.

[0005] The objective of this utility model can be achieved through the following technical solutions:

[0006] A harmonic reducer for a drone servo includes a housing, an input shaft, and an output shaft. A wave generator is housed within the housing. The wave generator and the input shaft are driven by bevel gear meshing. A flexible bearing is fitted around the outer periphery of the wave generator. A flexible wheel is fitted onto the flexible bearing. A rigid wheel is fitted around the outer periphery of the flexible wheel. The rigid wheel meshes with the flexible wheel via differential gear meshing. The housing comprises a first housing and a second housing that are separately fixed. The rigid wheel has a protruding clamping portion on its outer periphery at the center. The clamping portion clamps and fixes the rigid wheel between the first and second housings. Both ends of the rigid wheel are inserted into the first and second housings respectively, and the outer periphery surfaces of both ends of the rigid wheel are respectively abutted against the inner wall surfaces of the first and second housings. The output end of the flexible wheel is fixedly connected to the output shaft by bolts.

[0007] During operation, the input shaft rotates, driving the wave generator to rotate through bevel gear meshing. The rotation of the wave generator drives the flexible wheel to mesh with the rigid wheel through the flexible bearing, thereby enabling the output shaft to output power.

[0008] The rigid wheel and the housing are fixed separately, allowing them to be made of different materials. For example, the rigid wheel can be made of alloy structural steel, while the housing can be made of lightweight aerospace materials such as aluminum alloy, titanium alloy, or carbon fiber composites. This reduces the weight of the angle harmonic reducer. Furthermore, the clamping part on the outer circumference of the rigid wheel is fixed between the first and second housings, with both ends of the rigid wheel inserted into the first and second housings respectively. The outer circumference surfaces of the two ends of the rigid wheel are in contact with the inner walls of the first and second housings, ensuring the stability of the rigid wheel's fixation to the housing and guaranteeing its normal operation. The output end of the flexible wheel is directly fixed to the output shaft with bolts. Compared to existing technologies where the flexible wheel is indirectly connected to the output shaft via an output rigid wheel, the output end of the flexible wheel can be thinner and lighter, further reducing the weight of this angle harmonic reducer. Fixing the output end of the flexible wheel with bolts ensures stable fixation to the output shaft, guaranteeing its normal operation. Therefore, this angle harmonic reducer reduces weight while ensuring normal operation, thus contributing to the lightweight design of UAVs.

[0009] In the aforementioned angular harmonic reducer for a drone servo, a through hole is provided on the bottom wall of the first housing, and the input shaft passes through the through hole. The bottom wall of the first housing has a protruding strip that protrudes into the second housing, and the bottom wall of the second housing has a recess. The protruding strip is embedded in the recess, and the top surface of the protruding strip is in contact with the top surface of the recess.

[0010] The use of protrusions and recesses positions the first and second housings vertically, ensuring accurate positioning and facilitating the normal and stable operation of the angle harmonic reducer. Furthermore, the protrusions increase the structural strength of the bottom wall of the first housing, reducing the impact of through-holes on structural strength. This ensures structural stability of the housing without increasing its weight.

[0011] In the aforementioned UAV servo angular harmonic reducer, a locating pin is fixed to the clamping part, and one end of the locating pin is inserted into the second housing. When assembling the rigid wheel, one end of the rigid wheel can be inserted into the second housing first, along with the locating pin, and then the first housing can be fitted onto the other end of the rigid wheel, allowing the protrusion to embed into the recess. The locating pin circumferentially positions the rigid wheel and the second housing, facilitating assembly and ensuring the normal and stable operation of the angular harmonic reducer.

[0012] In the aforementioned angular harmonic reducer for the UAV servo, a first bearing is provided between the output shaft and the first housing, a second bearing is provided between the output shaft and the second housing, the output shaft passes through the wave generator, and an intermediate bearing is provided between the output shaft and the wave generator.

[0013] The output shaft forms two support points through the first and second bearings, which makes the output shaft rotate stably on the housing. The intermediate bearing is used to support the wave generator, making the wave generator rotate stably, thereby making the angle harmonic reducer work stably.

[0014] In the aforementioned angular harmonic reducer for a UAV servo, the outer circumferential surface of the output shaft has a shoulder located between the wave generator and the second bearing. The output end of the flexspline has a connecting disc, which is fitted onto the output shaft and clamped and fixed between the head of the bolt and the shoulder. The clamping and fixing of the connecting disc between the bolt head and the shoulder ensures the flexspline is stably fixed on the output shaft.

[0015] In the aforementioned angular harmonic reducer for a drone servo, a receiving groove is formed on the end face of the second housing facing away from the first housing. A limit pin is fixed on the output shaft, and the limit pin is located within the receiving groove. The limit pin is used to limit the rotation angle of the output shaft, preventing excessive rotation of the output shaft from affecting the stability of the drone's operation. In addition, the receiving groove can also reduce the weight of the second housing, which is beneficial to the lightweight design of the drone.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] The clamping part of the rigid wheel is fixed between the first and second housings. Both ends of the rigid wheel are inserted into the first and second housings respectively, with the outer circumferential surfaces of both ends abutting against the inner walls of the first and second housings. The output end of the flexible wheel is fixedly connected to the output shaft by a nut. This design ensures the normal operation of the angle harmonic reducer while reducing its weight, which is beneficial for the lightweight design of the UAV. The protrusions on the first housing not only position the first and second housings but also ensure the structural strength of the bottom wall of the first housing, contributing to the normal and stable operation of the angle harmonic reducer. A receiving groove is provided on the second housing, and the limiting pin on the output shaft is located within the receiving groove. This not only limits the rotation angle of the output shaft but also reduces the weight of the housing, further contributing to the lightweight design of the UAV. Attached Figure Description

[0018] Figure 1 This is a 3D diagram of the angular harmonic reducer of the servo motor of this drone.

[0019] Figure 2 This is a cross-sectional view of the angular harmonic reducer of the servo motor of this drone.

[0020] Figure 3 yes Figure 2 A cross-sectional view along the AA direction.

[0021] Figure 4 yes Figure 2 A cross-sectional view along the BB direction.

[0022] Figure 5 This is a 3D view of the first housing, rigid wheel, and second housing of the servo motor's angle harmonic reducer in this drone when disassembled.

[0023] In the figure, 1 is the housing; 1a is the first housing; 1a1 is the through hole; 1a2 is the protrusion; 1b is the second housing; 1b1 is the receiving groove; 1b2 is the notch; 2 is the wave generator; 3 is the input shaft; 4 is the output shaft; 4a is the shaft shoulder; 5 is the first bearing; 6 is the second bearing; 7 is the positioning pin; 8 is the intermediate bearing; 9 is the flexible bearing; 10 is the flexible wheel; 10a is the connecting plate; 11 is the rigid wheel; 11a is the clamping part; 12 is the bolt; 13 is the limit pin; and 14 is the limit plate. Detailed Implementation

[0024] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0025] like Figure 1 and Figure 2 As shown, a harmonic reducer for a drone servo includes a housing 1, an input shaft 3, and an output shaft 4. The housing 1 comprises a first housing 1a and a second housing 1b, which are fixed separately. A wave generator 2 is disposed inside the housing 1, and the wave generator 2 and the input shaft 3 are driven by bevel gear meshing. A through hole 1a1 is formed on the bottom wall of the first housing 1a, and the input shaft 3 passes through the through hole 1a1. A first bearing 5 is disposed between the output shaft 4 and the first housing 1a, and a second bearing 6 is disposed between the output shaft 4 and the second housing 1b. The right end of the output shaft 4 extends out of the second housing 1b. A receiving groove 1b1 is formed on the end face of the second housing 1b facing away from the first housing 1a, and a limit pin 13 is fixed on the output shaft 4, located within the receiving groove 1b1. The output shaft 4 passes through the wave generator 2, and an intermediate bearing 8 is disposed between the output shaft 4 and the wave generator 2. A shoulder is provided on the inner wall of the wave generator 2, and a limit plate 14 is fixed on the right end face of the wave generator 2. The intermediate bearing 8 is axially positioned between the limit plate 14 and the shoulder.

[0026] like Figure 2As shown, a flexible bearing 9 is mounted on the outer periphery of the wave generator 2. A flexible wheel 10 is mounted on the flexible bearing 9, and a rigid wheel 11 is mounted on the outer periphery of the flexible wheel 10. The rigid wheel 11 and the flexible wheel 10 mesh with a toothed engagement. The rigid wheel 11 has more teeth than the flexible wheel 10, typically two more teeth than the flexible wheel 10, for example, the rigid wheel 11 has 200 teeth and the flexible wheel 10 has 198 teeth. The output end of the flexible wheel 10 is fixedly connected to the output shaft 4 by bolts 12. The outer periphery of the output shaft 4 has a shoulder 4a located between the wave generator 2 and the second bearing 6. The output end of the flexible wheel 10 has a connecting disc 10a, which is mounted on the output shaft 4 and clamped and fixed between the head of the bolt 12 and the shoulder 4a. There are several bolts 12, evenly arranged circumferentially.

[0027] like Figure 2 , Figure 3 and Figure 4 As shown, the outer circumferential surface of the middle part of the rigid wheel 11 has a protruding clamping part 11a, which clamps and fixes between the first shell 1a and the second shell 1b. Both ends of the rigid wheel 11 are respectively inserted into the first shell 1a and the second shell 1b, and the outer circumferential surfaces of both ends of the rigid wheel 11 are respectively in contact with the inner wall surfaces of the first shell 1a and the second shell 1b. The bottom wall of the first shell 1a has a protruding rib 1a2 protruding towards the second shell 1b, and the bottom wall of the second shell 1b has a recess 1b2. The protruding rib 1a2 is embedded in the recess 1b2, and the top surface of the protruding rib 1a2 is in contact with the top surface of the recess 1b2. A positioning pin 7 is fixed on the clamping part 11a, and one end of the positioning pin 7 is inserted into the second shell 1b. Figure 5 As shown, when assembling the rigid wheel 11, one end of the rigid wheel 11 can be inserted into the second shell 1b first, and the locating pin 7 can be inserted into the second shell 1b. Then, the first shell 1a can be fitted onto the other end of the rigid wheel 11, so that the protrusion 1a2 is embedded into the recess 1b2. Finally, the first shell 1a, the rigid wheel 11 and the second shell 1b are fixedly connected by connecting bolts, that is, the connecting bolts pass through the second shell 1b and the rigid wheel 11 and are threadedly connected to the first shell 1a.

[0028] The rigid wheel 11 is fixed separately from the housing 1. This allows the housing 1 and the rigid wheel 11 to be made of different materials. For example, the rigid wheel 11 can be made of alloy structural steel, while the housing 1 can be made of lightweight aerospace materials such as aluminum alloy, titanium alloy, or carbon fiber composite materials. This reduces the weight of the angle harmonic reducer. The housing 1 can be made of 7075-T6 aluminum, which has fast thermal conductivity, quickly reducing the risk of performance degradation due to temperature rise, making it suitable for long-duration flight missions. The clamping part 11a on the outer circumference of the rigid wheel 11 clamps and fixes it between the first housing 1a and the second housing 1b. The outer circumferential surfaces at both ends of the rigid wheel 11 are respectively abutted against the inner wall surfaces of the first housing 1a and the second housing 1b, ensuring the stability of the rigid wheel 11 fixed on the housing 1 and guaranteeing its normal operation. Furthermore, the output end of the flexible wheel 10 is directly fixed to the output shaft 4 via bolts 12. Compared to the prior art where the flexible wheel 10 is indirectly connected to the output shaft 4 via the output rigid wheel 11, the output end of the flexible wheel 10 can be thinner and lighter than the output rigid wheel 11 in the prior art, further reducing the weight of this angle harmonic reducer. Fixing the output end of the flexible wheel 10 with bolts 12 ensures a stable connection between the output end of the flexible wheel 10 and the output shaft 4, guaranteeing normal operation of the flexible wheel 10. Therefore, this angle harmonic reducer can reduce weight while ensuring normal operation, thus contributing to the lightweight design of UAVs.

[0029] This angle harmonic reducer achieves a 480:1 reduction ratio through a two-stage reduction using 90-degree meshing bevel gears and harmonic gears, meeting the high reduction ratio requirements of UAV servos. The reducer features a compact design and small size; the rigid wheel 11 and housing 1 are made of different materials, achieving ultra-lightweight construction and meeting the requirements of UAV servos for compact size and light weight. This is particularly suitable for small or micro UAVs due to their high demands for lightweight design and space utilization. The tight gear meshing during transmission eliminates backlash, resulting in fast and precise servo response, ensuring the stability and anti-interference capabilities of the flight control system. This angle harmonic reducer is over 100 grams lighter than other harmonic reducers with the same output torque, achieving a higher torque density ratio and meeting the needs of UAV servos for high torque output within limited space (such as large-size control surfaces). This reducer uses a harmonic-grade flexible wheel 10 and rigid wheel 11 meshing method. The arc-shaped spiral bevel teeth have a high degree of overlap and continuous meshing, which can buffer instantaneous impact loads and meet the dynamic load changes (such as turbulence or maneuvering) during UAV flight.

[0030] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

Claims

1. A rotary harmonic reducer for a drone servo motor, comprising a housing (1), an input shaft (3), and an output shaft (4), wherein a wave generator (2) is disposed inside the housing (1), the wave generator (2) and the input shaft (3) are driven by bevel gear meshing, a flexible bearing (9) is fitted on the outer periphery of the wave generator (2), a flexible wheel (10) is fitted on the flexible bearing (9), a rigid wheel (11) is fitted on the outer periphery of the flexible wheel (10), the rigid wheel (11) meshes with the flexible wheel (10) by differential gear meshing, the housing (1) comprising a first shell (1a) and a second shell (1b) that are fixed separately, characterized in that, The outer circumferential surface of the middle part of the rigid wheel (11) has a protruding clamping part (11a). The clamping part (11a) is clamped and fixed between the first shell (1a) and the second shell (1b). The two ends of the rigid wheel (11) are respectively inserted into the first shell (1a) and the second shell (1b), and the outer circumferential surfaces of the two ends of the rigid wheel (11) are respectively in contact with the inner wall surface of the first shell (1a) and the inner wall surface of the second shell (1b). The output end of the flexible wheel (10) is fixedly connected to the output shaft (4) by bolts (12).

2. The angular harmonic reducer for a UAV servo according to claim 1, characterized in that, The bottom wall of the first shell (1a) is provided with a through hole (1a1), and the input shaft (3) passes through the through hole (1a1). The bottom wall of the first shell (1a) has a protruding strip (1a2) that protrudes toward the second shell (1b), and the bottom wall of the second shell (1b) has a recess (1b2). The protruding strip (1a2) is embedded in the recess (1b2), and the top surface of the protruding strip (1a2) is in contact with the top surface of the recess (1b2).

3. The angular harmonic reducer for a UAV servo according to claim 2, characterized in that, A positioning pin (7) is fixed on the clamping part (11a), and one end of the positioning pin (7) is inserted into the second shell (1b).

4. The angular harmonic reducer for a UAV servo according to any one of claims 1-3, characterized in that, A first bearing (5) is provided between the output shaft (4) and the first housing (1a), a second bearing (6) is provided between the output shaft (4) and the second housing (1b), the output shaft (4) passes through the wave generator (2), and an intermediate bearing (8) is provided between the output shaft (4) and the wave generator (2).

5. The angular harmonic reducer for a UAV servo according to claim 4, characterized in that, The outer circumferential surface of the output shaft (4) has a shoulder (4a) located between the wave generator (2) and the second bearing (6). The output end of the flexible wheel (10) has a connecting disc (10a). The connecting disc (10a) is fitted on the output shaft (4) and is clamped and fixed between the head of the bolt (12) and the shoulder (4a).

6. The angular harmonic reducer for a UAV servo according to any one of claims 1-3, characterized in that, The second shell (1b) has a receiving groove (1b1) on the end face facing away from the first shell (1a), and a limit pin (13) is fixed on the output shaft (4), and the limit pin (13) is located in the receiving groove (1b1).

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