Built-in variable-pitch pull rod sliding rail of cycloidal propeller and sliding rail parameter design method

Abstract

The invention relates to a cycloid propeller built-in variable pitch pull rod sliding rail and a sliding rail parameter design method, and belongs to the technical field of aircraft design. In order to solve the problems that in the prior art, a cycloid propeller cannot control the incidence angles of propeller blades at different positions, consequently, the size and direction of lift force are continuous and cannot be adjusted, a rotary wing type is adopted as a main lift force source, and compared with a fixed wing, the propelling efficiency is low, the method comprises the following steps that 1, the structure of a variable-pitch pull rod sliding rail is designed in the cycloid propeller; 2, parameters of the built-in variable-pitch pull rod sliding rail of the cycloidal propeller are determined according to the structure, determined in the step 1, of the built-in variable-pitch pull rod sliding rail of the cycloidal propeller and the installation position; and 3, according to the parameters of the variable-pitch pull rod sliding rail in the step 2, different paddle angles phi are set, and the shape of the built-in variable-pitch pull rod sliding rail of the cycloidal paddle is determined. According to the design method, the mounting position and specific parameters of the variable-pitch pull rod sliding rail can be rapidly designed, the method is simple, and calculation is convenient.

Description

Technical Field

[0001] The present invention relates to a preset slide rail and a slide rail parameter design method, in particular to a cycloid propeller built-in variable pitch pull rod slide rail and a slide rail parameter design method, belonging to the technical field of aircraft design. Background Art

[0002] In vertical / short takeoff and landing (VTOL) aircraft design, helicopters and tiltrotor aircraft utilize turboshaft or turboprop engines. While these technologies are relatively mature, they are relatively expensive and require complex reduction gearing and rotor systems. Flying cars (STOL aircraft) launched by major manufacturers are mostly powered by lithium batteries and feature a variety of configurations, including rotors, ducted fans, cycloidal propellers, fan wings, ducted fan composite wings, and deflected nozzle thrust. However, due to battery energy density limitations, these currently have short ranges and light payloads. Developing new, more efficient aerodynamic methods will have significant theoretical and practical significance.

[0003] Among the above-mentioned propulsion systems, the cycloidal propeller provides a new approach to solving the problem of short-distance takeoff and landing of aircraft, and is the main basis of the present invention. The cycloidal propeller is an omnidirectional vector propulsion device, generally composed of two or more blades. The blades of the cycloidal propeller undergo periodic changes during rotation, thereby generating lift. However, the cycloidal propeller generally has a high aerodynamic efficiency only at low Reynolds numbers. It cannot control the angle of attack of the blades at different positions, thereby achieving continuous adjustment of the lift size and direction. At the same time, due to the use of rotating airfoils as the main lift source, the propulsion efficiency is lower than that of fixed-wing propulsion.

[0004] To this end, the present invention aims to design a preset slide rail and a slide rail parameter design method for the pitch change problem of the cycloid propeller, thereby providing a reference for the design of the cycloid propeller blade pitch change mechanism. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem in the prior art that the cycloid propeller cannot control the angle of attack of the blades at different positions, resulting in the continuous non-adjustability of the lift size and direction, and the use of rotating airfoils as the main lift source, which has lower propulsion efficiency than fixed wings. A cycloid propeller with a built-in variable pitch pull rod slide and a slide rail parameter design method are provided.

[0006] In order to solve the above problems, this application is implemented through the following technical solutions: A cycloid propeller built-in variable pitch pull rod slide and slide rail parameter design method, which is special in that it includes the following steps: Step 1: Structural design of the built-in variable pitch pull rod guide rail for the cycloid propeller: Design the structure and installation position of the built-in variable pitch pull rod guide rail for the cycloid propeller based on the motion form of the cycloid propeller blades controlled by the built-in variable pitch pull rod guide rail for the cycloid propeller; Step 2: Determine the parameters of the cycloid propeller's built-in variable pitch pull rod slide rail according to the cycloid propeller's built-in variable pitch pull rod slide rail structure and installation position determined in step 1; Step 3: According to the pitch rod slide rail parameters in step 2, set different blade angles φ and determine the shape of the built-in pitch rod slide rail of the cycloid propeller.

[0007] The blade angle φ is the deflection angle of the line connecting the rotation centers OC toward the trailing edge of the airfoil chord line. The blade airfoil chord line refers to the line connecting the front end to the rear end of the blade.

[0008] Furthermore, the step 1 includes the following steps: Step 1.1. Determine the motion form of the cycloidal propeller blade: the cycloidal propeller blade swings around the blade rotation traction point, and the cycloidal propeller blade rotates around the drive disk through the blade rotation traction point. In the hovering state, the blade's trajectory is a circle, and in the forward state, the blade's trajectory is a cycloidal trajectory. Step 1.2: Design a blade drive mechanism for driving the cycloidal propeller blades to rotate. The blade drive mechanism includes a blade slideway provided on the cycloidal propeller blades, wherein the blade slideway is provided with a blade traction slider capable of moving within the blade slideway. Step 1.3. Design a pitch-changing mechanism for driving the blade drive mechanism: the pitch-changing mechanism includes a pitch-changing rod fixedly mounted on the driving disc and a pitch-changing stator fixedly mounted on the cycloidal propeller. The pitch-changing rod is provided with a slide rail groove, in which a rod slide rail is provided. A pitch-changing rod slider is mounted on the slide rail, a slider traction rod is mounted on the pitch-changing rod slider, and the other end of the slider traction rod is mounted on the blade traction slider. The pitch-changing stator is an irregular disc with a pitch-changing rod slide rail provided on its edge. A pitch-changing rod slider is embedded in the pitch-changing rod slide rail. Furthermore, the variable pitch pull rod slider in step 1.3 is hinged with a slider traction block; Furthermore, the step 2 includes the following steps: Step 2.1: Determine the mathematical model of the cycloid propeller's built-in variable pitch pull rod slide structure: According to the structure of the blade drive mechanism and the pitch change mechanism in step 1, a mathematical model is converted. The mathematical model is a quadrilateral formed by the center point O of the drive disc, the position point C of the blade, the position point B of the blade traction slider, and the position point A of the pitch change rod. The length L of the slider traction rod, i.e., the length of AB, the distance R between the blade rotation point and the disc center, i.e., the length of OC, the angle θ between the pitch change rod and the blade shaft, i.e., ∠AOC, are known quantities. The angle Φ between the blade chord and the shaft, i.e., ∠BCE, is the independent variable. The distance r between the pitch change slider and the shaft, i.e., the length OA, and the distance d between the blade traction slider and the traction point, i.e., BC, are the dependent variables to be solved. The distance between the variable pitch slider and the rotating shaft is the distance between the variable pitch pull rod slider and the center point of the driving disc; Step 2.2, calculate relevant parameters: Draw auxiliary line OB. According to known conditions, we know that angle ∠OCB = π - φ. Assuming that the distance CB from the blade traction slider to the traction point is d, the length of OB can be calculated as follows: , (1) ∠BOC is calculated by the following formula: , (2) ∠AOB=θ-∠BOC, (3) The parameter to be determined can be calculated by the following formula: , (4) In △AOB, according to the cosine formula, we can get: , (5) Substituting formula (4) into formula (5), we can obtain: , (6) exist Middle, L, R, are all known quantities, It is about unknown quantities OB, R, d, , and according to OB is about unknown quantities R, d, Therefore, the parameters to be determined in the above formula are R, d, ; Depend on It can be obtained that: when the angle φ is constant, the proportional relationship between the distance r between the variable pitch slider and the rotating shaft and the distance d between the blade traction slider and the traction point is obtained.

[0009] A cycloid propeller with a built-in variable pitch pull rod slide is characterized in that it includes a blade drive mechanism and a pitch change mechanism, the blade drive mechanism includes a blade slideway provided on the cycloid propeller blade, and a blade traction slider capable of moving in the blade slideway is installed in the blade slideway; The pitch-changing mechanism includes a pitch-changing pull rod fixedly mounted on the driving disc and a pitch-changing static disc fixedly mounted on the cycloidal propeller, the pitch-changing pull rod is provided with a slide rail groove, the slide rail groove is provided with a pull rod slide rail, the pull rod slide rail is provided with a pitch-changing pull rod slider, the pitch-changing pull rod slider is provided with a slider traction rod, and the other end of the slider traction rod is provided with a blade traction slider; The variable pitch static disc is an irregular disc, and a variable pitch pull rod slide rail is provided on the edge of the disc, and a variable pitch pull rod slider is embedded in the variable pitch pull rod slide rail.

[0010] Furthermore, the variable pitch pull rod slider is hinged with a slider traction block.

[0011] The design method of this application can quickly design the installation position and specific parameters of the variable pitch pull rod slide. The method is simple and easy to calculate. At the same time, the present invention uses a cycloid propeller with a built-in variable pitch pull rod slide structure to achieve a certain regular swing of the blades. The overall structure is simple and reliable, improving transmission efficiency and achieving greater lift and lift efficiency. It can achieve multi-axis linkage and precise response of the blades, and can actively change the swing angle of the blades while the cycloid propeller is moving, greatly improving the aerodynamic performance and maneuverability of the cycloid propeller, and has excellent controllability. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a flow chart of the method of the present invention; Figure 2 This is a schematic diagram of the cycloid propeller's built-in variable pitch pull rod slide structure; Figure 3 for Figure 2 Schematic diagram; Figure 4 for Figure 2 Mathematical model diagram of Figure 5 This is a schematic diagram of the blade angle periodic change in scheme 1; Figure 6 This is a schematic diagram of the blade angle periodic change in scheme 2; Figure 7 This is a schematic diagram of the periodic change of blade angles in the three-blade scheme; Figure 8 This is a schematic diagram of the shape of the variable pitch pull rod slide rail of Scheme 1; Figure 9 This is a schematic diagram of the shape of the variable pitch pull rod slide rail of Scheme 2; Figure 10 This is a schematic diagram of the shape of the variable pitch pull rod slide rail of Scheme 3; In the figure: 1. Blade slideway, 2. Blade traction slider, 3. Drive disc, 4. Pitch rod, 5. Pitch disc, 6. Rod guide rail, 7. Pitch rod slider, 8. Slider traction rod, 9. Pitch rod guide rail, 10. Cycloidal propeller blade, 11. Blade rotation traction point. A is the equivalent incoming flow velocity vector. DETAILED DESCRIPTION

[0013] The following provides specific embodiments of the present invention with reference to the accompanying drawings to further illustrate the structure of the present invention.

[0014] To facilitate understanding of the embodiments of the present invention, abbreviations and key terms that may be involved in the embodiments of the present invention are first explained or defined.

[0015] Example 1. A design method for a cycloidal propeller with a built-in variable pitch pull rod slide and slide rail parameters, the specific process is as follows Figure 1 As shown, the following steps are included: Step 1: Structural design of the built-in variable pitch pull rod guide rail for the cycloid propeller: Design the structure and installation position of the built-in variable pitch pull rod guide rail for the cycloid propeller based on the motion form of the cycloid propeller blades controlled by the built-in variable pitch pull rod guide rail for the cycloid propeller; Step 2: Determine the parameters of the cycloid propeller's built-in variable pitch pull rod slide rail according to the cycloid propeller's built-in variable pitch pull rod slide rail structure and installation position determined in step 1; Step 3: According to the pitch rod slide rail parameters in step 2, set different blade angles φ and determine the shape of the built-in pitch rod slide rail of the cycloid propeller.

[0016] The blade angle φ is the angle at which the line connecting the center of rotation OC deflects toward the trailing edge of the airfoil chord line. The airfoil chord line is the line connecting the front and rear ends of the blade. Wherein, the step 1 includes the following steps: Step 1.1. Determine the motion form of the cycloidal propeller blade: The cycloidal propeller blade swings around the blade rotation traction point 11. The cycloidal propeller blade rotates around the drive disk through the blade rotation traction point 11. The blade's trajectory in the hovering state is circular, and in the forward state, the blade's trajectory is cycloidal. The cycloidal propeller blade undergoes periodic changes during rotation, thereby generating lift. Step 1.2: Design a blade drive mechanism for driving the cycloidal propeller blade to rotate: the blade drive mechanism includes a blade slideway 1 provided on the cycloidal propeller blade 10, wherein the blade slideway 1 is provided with a blade traction slider 2 capable of moving within the blade slideway 1; Step 1.3. Design a pitch-changing mechanism for driving the blade drive mechanism: The pitch-changing mechanism includes a pitch-changing rod 4 fixedly mounted on the drive disc 3 and a pitch-changing stator 5 fixedly mounted on the cycloidal propeller. The pitch-changing rod 4 has a slide rail groove, in which a rod slide rail 6 is disposed. A pitch-changing rod slider 7 is mounted on the slide rail 6. A slider traction rod 8 is mounted on the pitch-changing rod slider 7. The other end of the slider traction rod 8 is mounted on the blade traction slider 2. The variable pitch stator disc 5 is an irregular disc, with a variable pitch rod slide rail 9 provided on its edge. The variable pitch rod slide rail 9 is embedded with a variable pitch rod slider 7. The variable pitch rod slider 7 is hinged with a slider traction rod 8.

[0017] refer to Figure 2-Figure 3 As shown, in this embodiment, the cycloid blade 10 is connected to the drive disc 3 through a rotating pair, and the rotation of the drive disc 3 is driven by a power mechanism. The power mechanism belongs to the existing technology and will not be described here.

[0018] One end of the pitch rod slider 7 described in this embodiment is embedded in the pitch rod slide rail 9, and the other end is installed in the pull rod slide rail 6. When the driving disc 3 rotates to drive the pitch rod 4 to rotate, the pull rod slide rail 6 rotates. Since the pitch rod stator 5 does not rotate with the driving disc 3, the pitch rod slider 7 rotates in the pitch rod slide rail 9 at this time. The pitch rod slider 7 slides up and down along the pull rod slide rail 6 while rotating. The pitch rod slider 7 drives the slider traction rod 8 to rotate, and then drives the blade traction slider 2 to rotate in the blade slideway 1. Since the pitch stator 5 is an irregular disc, the pitch rod slide rail 9 set on its edge is also irregular, which causes the distance between the blade traction slider and the traction point to change, ensuring that the cycloid propeller blade 10 rotates around the blade rotation traction point 11, thereby generating a change in pitch angle.

[0019] Wherein, the step 2 comprises the following steps: Step 2.1: Determine the mathematical model of the cycloid propeller's built-in variable pitch pull rod slide structure: According to the structure of the blade drive mechanism and the pitch change mechanism in step 1, they are converted into a mathematical model. The mathematical model is a quadrilateral formed by the center point O of the drive disc, the position point C of the blade, the position point B of the blade traction slider, and the position point A of the pitch change rod. The length L of the slider traction rod, i.e., the length of AB, the distance R between the blade rotation point and the center of the disc, i.e., the length of OC, the angle θ between the pitch change rod and the blade shaft, i.e., ∠AOC, are known quantities. The angle Φ between the blade chord and the shaft, i.e., ∠BCE, is the independent variable. The distance r between the pitch change slider and the shaft, i.e., the length of OA, and the distance d between the blade traction slider and the traction point, i.e., BC, are the dependent variables to be solved, as shown in the following example: Figure 4 As shown; The distance between the variable pitch slider and the rotating shaft is the distance between the variable pitch pull rod slider and the center point of the driving disc; Step 2.2, calculate relevant parameters: Draw auxiliary line OB. According to known conditions, we know that angle ∠OCB = π - φ. Assuming that the distance CB from the blade traction slider to the traction point is d, the length of OB can be calculated as follows: , (1) ∠BOC is calculated by the following formula: , (2) ∠AOB=θ-∠BOC, (3) The parameter to be determined can be calculated by the following formula: , (4) In △AOB, according to the cosine formula, we can get: , (5) Substituting formula (4) into formula (5), we can obtain: , (6) exist Middle, L, R, are all known quantities, It is about unknown quantities OB, R, d, , and according to OB is about unknown quantities R, d, Therefore, the parameters to be determined in the above formula are R, d, ; Depend on It can be obtained that: when the angle φ is constant, the proportional relationship between the distance r between the variable pitch slider and the rotating shaft and the distance d between the blade traction slider and the traction point is obtained.

[0020] Among them, step 3 is based on the variable pitch pull rod slide rail parameter design method of step 2, taking L=20cm, R=30cm, θ=30°, and now three variable pitch schemes are proposed. The specific information of the variable pitch schemes is shown in Table 1.

[0021] Table 1 Pitch variation scheme information table .

[0022] According to the mathematical model, the shapes of the pitch-changing rod slide rails corresponding to the three pitch-changing schemes are calculated as follows: Figures 8-10 shown.

[0023] Example 2. A cycloid propeller with a built-in variable pitch pull rod slide designed using the method described in Example 1 includes a blade drive mechanism and a pitch change mechanism. The blade drive mechanism includes a blade slideway 1 disposed on a cycloid propeller blade 10, and a blade traction slider 2 capable of moving within the blade slideway 1 is installed within the blade slideway 1. The pitch-changing mechanism includes a pitch-changing rod 4 fixedly mounted on a driving disc 3 and a pitch-changing static disc 5 fixedly mounted on a cycloidal propeller. A slide rail groove is provided on the pitch-changing rod 4, a rod slide rail 6 is provided in the slide rail groove, a pitch-changing rod slider 7 is mounted on the rod slide rail 6, a slider traction rod 8 is mounted on the pitch-changing rod slider 7, and the other end of the slider traction rod 8 is mounted on the blade traction slider 2; The variable pitch stator disc 5 is an irregular disc, with a variable pitch rod slide rail 9 provided on its edge. The variable pitch rod slide rail 9 is embedded with a variable pitch rod slider 7. The variable pitch rod slider 7 is hinged with a slider traction rod 8.

[0024] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope defined by the appended claims.

Claims

1. A cycloid propeller built-in variable pitch pull rod slide and slide rail parameter design method, characterized by: The following steps are involved: Step 1: Structural design of the built-in variable pitch pull rod slide rail of the cycloid propeller: Design the structure and installation position of the built-in variable pitch pull rod slide of the cycloid propeller according to the movement form of the built-in variable pitch pull rod slide of the cycloid propeller to control the blade of the cycloid propeller; Step 2: Determine the parameters of the cycloid propeller's built-in variable pitch pull rod slide rail according to the cycloid propeller's built-in variable pitch pull rod slide rail structure and installation position determined in step 1; Step 3: According to the pitch rod slide rail parameters in step 2, set different blade angles φ and determine the shape of the built-in pitch rod slide rail of the cycloid propeller.

2. A cycloid propeller built-in variable pitch pull rod slide and slide rail parameter design method according to claim 1, characterized in that: The step 1 comprises the following steps: Step 1.

1. Determine the motion form of the cycloidal propeller blade: the cycloidal propeller blade swings around the blade rotation traction point, and the cycloidal propeller blade rotates around the drive disk through the blade rotation traction point. In the hovering state, the blade's trajectory is a circle, and in the forward state, the blade's trajectory is a cycloidal trajectory. Step 1.2: Design a blade drive mechanism to drive the cycloidal propeller blades. Step 1.3: Design the pitch-changing mechanism that drives the blade drive mechanism.

3. The method for designing the built-in variable pitch pull rod slide rail and slide rail parameters for a cycloid propeller according to claim 2, characterized in that: The blade drive mechanism in step 1.2 includes a blade slideway provided on the cycloidal propeller blade, wherein the blade slideway is provided with a blade traction slider capable of moving in the blade slideway; The pitch-changing mechanism includes a pitch-changing pull rod fixedly mounted on the driving disc and a pitch-changing static disc fixedly mounted on the cycloidal propeller, the pitch-changing pull rod is provided with a slide rail groove, the slide rail groove is provided with a pull rod slide rail, the pull rod slide rail is provided with a pitch-changing pull rod slider, the pitch-changing pull rod slider is provided with a slider traction rod, and the other end of the slider traction rod is provided with a blade traction slider; The variable pitch static disc is an irregular disc, and a variable pitch pull rod slide rail is provided on the edge of the disc, and a variable pitch pull rod slider is embedded in the variable pitch pull rod slide rail.

4. A cycloid propeller built-in variable pitch pull rod slide and slide rail parameter design method according to claim 3, characterized in that: The variable pitch pull rod slider in step 1.3 is hinged with a slider traction block.

5. A cycloidal propeller built-in variable pitch pull rod slide and slide rail parameter design method according to any one of claims 1 to 3, characterized in that: The step 2 comprises the following steps: Step 2.1, determine the mathematical model of the variable pitch pull rod slide structure built into the cycloid propeller; Step 2.2: Calculate relevant parameters.

6. The method for designing the built-in variable pitch pull rod slide rail and slide rail parameters for a cycloid propeller according to claim 5, characterized in that: The step 2.1 is as follows: According to the structure of the blade drive mechanism and the pitch change mechanism in step 1, they are converted into a mathematical model. The mathematical model is a quadrilateral formed by the center point O of the drive disc, the position point C of the blade, the position point B of the blade traction slider, and the position point A of the pitch change rod. The length L of the slider traction rod, i.e., the length of AB, the distance R between the blade rotation point and the center of the disc, i.e., the length of OC, the angle θ between the pitch change rod and the blade shaft, i.e., ∠AOC, are known quantities. The angle Φ between the blade chord and the shaft, i.e., ∠BCE, is the independent variable. The distance r between the pitch change slider and the shaft, i.e., the length OA, and the distance d between the blade traction slider and the traction point, i.e., BC, are the dependent variables to be solved.

7. The method for designing the built-in variable pitch pull rod slide rail and slide rail parameters for a cycloid propeller according to claim 6, characterized in that: The distance between the variable pitch slider and the rotating shaft is the distance between the variable pitch pull rod slider and the center point of the driving disc.

8. The method for designing the built-in variable pitch pull rod slide rail and slide rail parameters for a cycloid propeller according to claim 5, characterized in that: The step 2.2 is as follows: Draw auxiliary line OB. According to known conditions, the angle ∠OCB = π - φ, and the distance CB from the blade traction slider to the traction point = d. Then the length of OB can be calculated by the following formula: ， （1） ∠BOC is calculated by the following formula: ， （2） ∠AOB=θ-∠BOC, (3) The parameter to be determined can be calculated by the following formula: ， （4） In △AOB, according to the cosine formula, we can get: ，（5） Substituting formula (4) into formula (5), we can obtain: ， （6） exist Middle, L, R, are all known quantities, It is about unknown quantities OB, R, d, , and according to OB is about unknown quantities R, d, Therefore, the parameters to be determined in the above formula are R, d, ; Depend on It can be obtained that: when the angle φ is constant, the proportional relationship between the distance r between the variable pitch slider and the rotating shaft and the distance d between the blade traction slider and the traction point is obtained.

9. A cycloid propeller with a built-in variable pitch pull rod slide designed according to the method of claims 1-8, characterized in that: It includes a blade drive mechanism and a pitch change mechanism, wherein the blade drive mechanism includes a blade slideway provided on the cycloid propeller blade, and a blade traction slider capable of moving in the blade slideway is installed in the blade slideway; The pitch-changing mechanism includes a pitch-changing pull rod fixedly mounted on the driving disc and a pitch-changing static disc fixedly mounted on the cycloidal propeller, the pitch-changing pull rod is provided with a slide rail groove, the slide rail groove is provided with a pull rod slide rail, the pull rod slide rail is provided with a pitch-changing pull rod slider, the pitch-changing pull rod slider is provided with a slider traction rod, and the other end of the slider traction rod is provided with a blade traction slider; The variable pitch static disc is an irregular disc, and a variable pitch pull rod slide rail is provided on the edge of the disc, and a variable pitch pull rod slider is embedded in the variable pitch pull rod slide rail.

10. A cycloid propeller with a built-in variable pitch pull rod slide rail according to claim 9, characterized in that: The variable pitch pull rod slider is hinged with a slider traction block.

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