Method for adjusting flapping vibration of elastic constant-speed universal hinge of rotor hub

Abstract

The invention belongs to the technical field of tilt-rotor aircraft rotor system design, and particularly relates to a method for adjusting flapping vibration of an elastic constant-speed universal hinge of a rotor hub. By reasonably configuring the radial rigidity of the elastic ball bowl of the elastic constant-speed universal hinge and the axial rigidity of the two universal hinges of the elastic ball hinge connecting rod, the transverse displacement of the elastic constant-speed universal hinge when the rotor hub flaps is reduced. Therefore, the three-time rotating speed transverse vibration of the elastic constant-speed universal hinge is reduced, the additional counterweight weight of the tilt-rotor aircraft propeller hub shock absorber is reduced by three times, and meanwhile the structural design of the constant-speed universal hinge is optimized.

Description

[0001] Technical Field This invention belongs to the technical field of tiltrotor aircraft rotor system design, specifically relating to a method for adjusting the flapping vibration of a rotor hub elastic constant speed universal joint. Background Technology

[0002] A tiltrotor aircraft is a type of aircraft that combines the characteristics of helicopters and fixed-wing aircraft, capable of switching between vertical takeoff and landing (VTOL) and high-speed cruise. Its core feature is its tiltable rotor, allowing it to rotate like a helicopter during VTOL and remain stationary like a fixed-wing aircraft during level flight. Tiltrotor aircraft are well-suited for missions in complex terrain or urban environments.

[0003] A constant velocity universal joint is a mechanical device used to transmit power, ensuring smooth power transmission even when the input and output shafts are at an angle. Common metal constant velocity universal joints mainly include ball cage type, double offset type, three ball pin type, and cross-axis type. These metal constant velocity universal joints are primarily used in the automotive industry.

[0004] Tiltrotor aircraft rotor hubs typically use flexible constant-speed universal joints, as shown in the attached diagram. Figure 1 and 2 As shown in the figure. The elastic ball cup (the elastic ball cup is divided into an upper ball cup and a lower ball cup, which are symmetrical and collectively referred to as elastic ball cups; only one side of the ball cup is shown in the figure), the elastic ball hinge connecting rod, and the central component are the core components of the elastic constant velocity universal joint.

[0005] One end of the flexible ball cup is connected to the propeller hub support arm, and the other end is connected to the main shaft via a central component. Simultaneously, both ends of the flexible ball cup are connected to the two ball joints of the flexible ball hinge connecting rod. Both the flexible ball cup and the flexible ball hinge connecting rod utilize flexible bearings. Flexible bearings are constructed by alternating layers of thin metal and rubber sheets bonded together, achieving the functions of various bearings such as metal ball bearings, universal joint bearings, and sliding bearings through the directional deformation of the rubber. Flexible bearings do not require lubrication from metal bearings and offer advantages such as good maintainability and high reliability.

[0006] When the rotor hub support plane (also known as the rotor disk plane) is not perpendicular to the main shaft, i.e., when the rotor disk is tilted, the elastic constant-velocity universal joint will generate lateral vibration. This vibration occurs because, when the rotor disk is tilted, the elastic ball joint linkage's trajectory differs at different positions on the rotational circumference. The elastic ball cup needs to generate lateral displacement in the rotor disk direction to coordinate the circumferential rotation of the elastic ball joint linkage. Since the diameter of the elastic element in the elastic bearing of the elastic ball joint linkage is smaller than that in the elastic ball cup bearing, the axial stiffness of the elastic ball joint linkage is generally much higher than the radial stiffness of the elastic ball cup (in the direction of lateral displacement of the elastic constant-velocity universal joint). Therefore, when the rotor disk is tilted, the center of the elastic ball cup shifts, causing the entire rotor to generate lateral vibration at three times the rotational speed.

[0007] The vibration increases with the tilt angle of the constant-speed universal joint. To reduce the lateral vibration at three times the rotational speed, a centrifugal pendulum damper is often used. However, this method increases the hub weight significantly and reduces the load capacity. Summary of the Invention

[0008] The purpose of this invention is to provide a method for adjusting the flapping vibration of a rotor hub's elastic constant-speed universal joint. By rationally configuring the radial stiffness of the elastic ball joint's cup and the axial stiffness of the two universal joints in the elastic ball joint connecting rod, the lateral displacement of the elastic constant-speed universal joint during rotor hub flapping is reduced. This reduces the lateral vibration of the elastic constant-speed universal joint by three times its rotational speed, reduces the additional counterweight weight of the tiltrotor aircraft's rotor hub vibration damper by three times, and also optimizes the structural design of the constant-speed universal joint.

[0009] The technical solution of the present invention: In order to achieve the above-mentioned objective, according to the first aspect of the present invention, a method for adjusting the flapping vibration of a rotor hub elastic constant speed universal joint is proposed, which refers to reducing the lateral displacement vibration when the elastic constant speed universal joint flaps by reasonably distributing the stiffness of the elastic ball cup and the elastic ball joint connecting rod of the elastic constant speed universal joint.

[0010] The adjustment method includes the following steps: S1. It is determined that a three-arm elastic constant speed universal joint is used as the central flapping joint of the propeller hub. S2. Establish a simplified calculation model for the axial stiffness and radial stiffness of the elastic bearing assembly in the elastic ball cup and / or the elastic ball hinge connecting rod; S3. Based on the maximum tensile force that the propeller hub needs to withstand, determine the axial stiffness requirement of the elastic ball cup. The axial stiffness requirement is such that the axial displacement of the elastic ball cup under the maximum tensile force is ≤1mm. S4. Based on the axial stiffness requirement of the elastic ball cup determined in step S3, the main structural dimensions of the elastic bearing assembly of the elastic ball cup are initially determined. S5. Based on the main structural dimensions determined in step S4, the radial stiffness (k_(radial-bowl)) of the elastic ball cup is calculated using the simplified radial stiffness calculation model. S6. Based on the structural space layout, the main structural dimensions of the elastic bearing assembly of the elastic ball joint connecting rod are initially determined; S7. Based on the main structural dimensions determined in S6, the axial stiffness (k_(axial-spherical joint)) of the elastic ball joint is calculated using the simplified axial stiffness calculation model. S8. The radial stiffness (k_(radial-spherical joint)) of the elastic ball cup is compared with the axial stiffness (k_(axial-spherical joint)) of the elastic ball joint, and the structural dimensions of the elastic ball joint are adjusted so that k_(axial-spherical joint) ≤ 1 / 2 k_(radial-spherical joint). In one possible embodiment, in step S2, the simplified calculation formula for the axial stiffness of each layer of the elastic ball joint is:

[0011] The formula for calculating the total axial stiffness of an elastic ball joint (or elastic ball cup) is as follows:

[0012] in: : Indicates the axial stiffness of a single-layer rubber body in a metal-rubber laminate structure, in N / mm; : Represents the axial force exerted on a single layer of rubber in a metal-rubber laminate structure, in N; : Represents the axial displacement of a single layer of rubber in a metal-rubber laminate structure after being subjected to force, in mm; : Indicates the axial length of a single layer of rubber in a metal and rubber laminate structure, in mm; : Represents the radius of a single layer of rubber in a metal-rubber laminate structure, in mm; : Indicates the thickness of a single layer of rubber in a metal and rubber laminate structure, in mm; : Represents the shear modulus of a single layer of rubber in a metal-rubber laminate structure, in N / mm²; : Indicates the total axial stiffness of the metal and rubber laminate structure; : Indicates the number of layers in a metal and rubber laminate structure.

[0013] In one possible embodiment, in step S2, the simplified calculation formula for the radial stiffness of each layer of the elastic body in the elastic ball cup bearing assembly is as follows:

[0014] The formula for calculating the radial stiffness of an elastic ball cup is:

[0015] in: : Indicates the radial stiffness of a single-layer rubber body in a metal-rubber laminate structure, in N / mm; : Represents the radial force exerted on a single layer of rubber in a metal-rubber laminate structure, in N; : Represents the radial displacement of a single layer of rubber in a metal-rubber laminate structure after being subjected to force, in mm; : Indicates the axial length of a single layer of rubber in a metal and rubber laminate structure, in mm; : Represents the radius of a single layer of rubber in a metal-rubber laminate structure, in mm; : Indicates the thickness of a single layer of rubber in a metal and rubber laminate structure, in mm; : Represents the elastic modulus of a single layer of rubber in a metal-rubber laminate structure, in N / mm²; : Indicates the total radial stiffness of the metal and rubber laminate structure; : Indicates the number of layers in a metal and rubber laminate structure.

[0016] In one possible embodiment, in step S4, based on the axial stiffness of the elastic ball cup... The requirements determine the main structural dimensions of the elastic ball cup, including the axial length of the single-layer rubber body in the metal and rubber laminate structure. ,radius , and number of layers Four parameters.

[0017] In one possible embodiment, in step S6, the main structural dimensions of the elastic ball joint link include the axial length of the single-layer rubber body of the metal and rubber laminate structure. ,radius , and number of layers Four parameters.

[0018] In one possible embodiment, in S8, when k_(axial-ball joint) ≤ 1 / 2 k_(radial-ball cup), the swinging vibration of the elastic constant velocity universal joint is reduced to 1 / 3 of its maximum value.

[0019] According to a second aspect of the present invention, a rotor hub elastic constant speed universal joint is provided, employing the aforementioned method for adjusting the flapping vibration of the rotor hub elastic constant speed universal joint. include: A central connector for the spindle; An elastic ball cup assembly is fitted onto the central connector of the main shaft; At least three elastic ball joints are connected to the central connector of the main shaft via a first elastic ball joint on their inner side and to the corresponding blade support arm via a second elastic ball joint on their outer side. The radial stiffness (k_(radial-ball cup)) of the elastic ball cup assembly and the axial stiffness (k_(axial-ball hinge)) of the elastic ball hinge link satisfy the following relationship: k_(axial-ball hinge) ≤ 1 / 2 k_(radial-ball cup).

[0020] In one possible embodiment, the elastic ball cup assembly includes an upper elastic ball cup and a lower elastic ball cup that are symmetrically mounted vertically.

[0021] In one possible embodiment, both the elastic ball cup assembly and the elastic bearing assembly in the elastic ball hinge link are metal and rubber laminate structures.

[0022] In one possible embodiment, the axial stiffness of the elastic ball cup assembly is configured such that it produces an axial displacement of ≤1 mm when the hub is subjected to maximum tensile force.

[0023] The advantages of this invention are: The method of this invention employs a coordinated matching of the radial stiffness of the elastic ball joint and the axial stiffness of the elastic ball joint connecting rod, allowing a portion of the lateral displacement of the flapping motion of the tilt rotor hub's elastic constant-velocity universal joint to be replaced by the axial movement of the elastic ball joint connecting rod. This reduces the overall lateral movement of the constant-velocity universal joint, and consequently reduces vibration. Without adding extra weight, rotor hub weight reduction can be achieved through optimized design. Attached Figure Description

[0024] To more clearly illustrate the technical solutions implemented in this invention, the accompanying drawings used in the embodiments of this invention will be briefly explained below. Obviously, the drawings described below are merely some embodiments of this invention. Those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0025] Figure 1Exploded view of the elastic constant-velocity universal joint of the rotor hub of a tiltrotor aircraft Figure 2 Schematic diagram of the elastic constant-speed universal joint of the rotor hub of a tiltrotor aircraft Figure 3 Schematic diagram of an elastic constant-speed universal joint and elastic ball joint connecting rod for a tiltrotor aircraft rotor hub. Figure 4 Schematic diagram of an elastic constant-speed universal joint elastic ball joint for a tiltrotor aircraft rotor hub Figure 5 Schematic diagram of single-layer rubber structure parameters and axial stiffness of elastic bearing Figure 6 Schematic diagram of single-layer rubber structure parameters and radial stiffness of elastic bearing Figure 7 Flowchart of the design process for the radial stiffness of the elastic ball joint and the axial stiffness of the elastic ball joint link. (1) is the elastic ball joint connecting rod, (2) is the central component connecting the elastic constant speed universal joint to the main shaft, (3) is the elastic ball cup, (4) is the main rotor shaft, (5) is the outer shell of the elastic ball joint connecting rod, (6) and (7) are the inner shell of the elastic ball joint connecting rod, (8) and (9) are the elastic bearing parts of the elastic ball joint connecting rod, which are composed of multiple layers of metal and rubber cross-layers, (10) is the connection end between the elastic ball cup and the rotor hub arm, (11) is the connection end between the elastic ball cup and the main shaft, (12) is a part of the connection end between the elastic ball cup and the rotor hub arm, which is connected to the elastic ball joint connecting rod, (13) is the elastic bearing part of the elastic ball cup, which is composed of multiple layers of metal and rubber cross-layers, (14) is the radial displacement direction of the elastic bearing, and (15) is the axial displacement direction of the elastic bearing. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0028] A method for adjusting the flapping vibration of a rotor hub with an elastic constant-speed universal joint includes the following steps: Step 1: Determine the three-arm elastic constant-speed universal joint as the central flapping joint of the propeller hub. Flexible constant-velocity universal joints offer advantages such as simple maintenance and high reliability. The three-arm flexible constant-velocity universal joint is chosen as the central swinging hinge of the propeller hub. Its main structural components include: a flexible ball cup, a central connecting component of the main shaft, and a flexible ball hinge connecting rod. Both the flexible ball cup and the flexible ball hinge connecting rod contain flexible bearing assemblies. The flexible bearing refers to a component that enables the hinge function, composed of a metal and rubber laminate structure. The flexible ball cup consists of two symmetrically mounted flexible ball cups, one upper and one lower. Figure 1 and attached Figure 2 Only the flexible lower ball bowl is shown in the image.

[0029] Step 2: Establish a simplified calculation formula for the axial stiffness of an elastic ball joint (or elastic ball cup). Simplified calculation formula for axial stiffness of elastic ball joint (or elastic ball cup), structural dimension parameters and schematic diagram are attached. Figure 5 The simplified formula for calculating the axial stiffness of each elastic element in an elastic ball joint is:

[0030] The formula for calculating the total axial stiffness of an elastic ball joint (or elastic ball cup) is as follows:

[0031] in: : Indicates the axial stiffness of a single-layer rubber body in a metal-rubber laminate structure, in N / mm; : Represents the axial force exerted on a single layer of rubber in a metal-rubber laminate structure, in N; : Represents the axial displacement of a single layer of rubber in a metal-rubber laminate structure after being subjected to force, in mm; : Indicates the axial length of a single layer of rubber in a metal and rubber laminate structure, in mm; : Represents the radius of a single layer of rubber in a metal-rubber laminate structure, in mm; : Indicates the thickness of a single layer of rubber in a metal and rubber laminate structure, in mm; : Represents the shear modulus of a single layer of rubber in a metal-rubber laminate structure, in N / mm²; : Indicates the total axial stiffness of the metal and rubber laminate structure; : Indicates the number of layers in a metal and rubber laminate structure.

[0032] Step 3: Establish a simplified calculation formula for the radial stiffness of an elastic ball joint (or elastic ball cup). Simplified calculation formula for radial stiffness of elastic ball joint (or elastic ball cup), structural dimension parameters and schematic diagram are attached. Figure 6 The simplified formula for calculating the radial stiffness of each elastic element in an elastic ball joint (or elastic ball cup) is as follows:

[0033] The formula for calculating the radial stiffness of an elastic ball joint (or elastic ball cup) is as follows:

[0034] in: : Indicates the radial stiffness of a single-layer rubber body in a metal-rubber laminate structure, in N / mm; : Represents the radial force exerted on a single layer of rubber in a metal-rubber laminate structure, in N; : Represents the radial displacement of a single layer of rubber in a metal-rubber laminate structure after being subjected to force, in mm; : Indicates the axial length of a single layer of rubber in a metal and rubber laminate structure, in mm; : Represents the radius of a single layer of rubber in a metal-rubber laminate structure, in mm; : Indicates the thickness of a single layer of rubber in a metal and rubber laminate structure, in mm; : Represents the elastic modulus of a single layer of rubber in a metal-rubber laminate structure, in N / mm²; : Indicates the total radial stiffness of the metal and rubber laminate structure; : Indicates the number of layers in a metal and rubber laminate structure.

[0035] Step 4: Determine the axial stiffness requirements of the elastic ball cup. Axial stiffness of elastic ball cup When the maximum tensile force on the propeller hub is equal to the maximum tensile force, an axial displacement of ≤1mm will occur.

[0036] Step 5: Preliminary determination of the main structural dimensions of the elastic ball cup like Figure 4 As shown, based on the axial stiffness of the elastic ball cup The requirements determine the main structural dimensions of the elastic ball cup, including the axial length of the single-layer rubber body in the metal and rubber laminate structure. ,radius , and number of layers Four parameters.

[0037] Note: Based on the preliminarily determined main structural dimensions of the elastic ball cup and the relevant materials selected, the strength of the elastic ball cup should also meet the design requirements.

[0038] Step 6: Calculate the radial stiffness of the elastic ball cup. Based on the axial length of the single-layer rubber body of the metal and rubber laminate structure of the elastic ball cup, which was initially determined in step five. ,radius , and number of layers Four parameters are used to calculate the radial stiffness of the elastic ball cup, referring to step three. .

[0039] Step 7: Preliminary determination of the main structural dimensions of the elastic ball joint connecting rod The main structural dimensions of the elastic ball joint linkage, including the axial length of the single-layer rubber body in the metal and rubber laminate structure, are determined according to the structural space layout requirements. ,radius , and number of layers Four parameters.

[0040] Note: The elastic ball joint link has two elastic ball joints with identical stiffness properties, and the stiffness design method for each elastic ball joint is the same. Furthermore, based on the preliminarily determined main structural dimensions of the elastic ball joint link and the selected materials, the strength of the elastic ball joint link should also simultaneously meet the design requirements.

[0041] Step 8: Calculate the axial stiffness of the elastic ball joint link. like Figure 3 As shown, based on the axial length of the single-layer rubber body of the metal and rubber laminate structure of the elastic ball joint initially determined in step seven. ,radius , and number of layers Four parameters are used to calculate the axial stiffness of the elastic ball joint, referring to step two. .

[0042] Step 9: Compare the radial stiffness of the elastic ball cups Axial stiffness of the elastic ball joint link

[0043] In theory, the axial stiffness of the elastic ball joint should be as small as possible to effectively reduce the swing vibration of the elastic constant velocity universal joint. Due to structural size limitations, the axial stiffness of the elastic ball joint should be at least ≤1 / 2 of the radial stiffness of the elastic ball cup, so that the swing vibration of the elastic constant velocity universal joint will be reduced to 1 / 3 of its maximum value.

[0044] The swing vibration of an elastic constant velocity universal joint is directly related to the radial stiffness of the elastic ball cup and the axial stiffness of the elastic ball joint connecting rod.

[0045] If the radial stiffness of the elastic ball cup is much smaller than the axial stiffness of the elastic ball hinge link, then the swinging vibration of the elastic constant velocity universal joint is basically zero. If the radial stiffness of the elastic ball cup is much greater than the axial stiffness of the elastic ball hinge link, then the swinging vibration of the elastic constant velocity universal joint is at its maximum value. If the radial stiffness of the universal joint ball cup is equal to the axial stiffness of the elastic ball joint link, then the swing vibration of the elastic constant velocity universal joint is 1 / 2 of the maximum value.

[0046] Step 10: Adjust the axial stiffness of the elastic ball joint connecting rod. If the requirements of step nine are not met, the axial stiffness of the elastic ball joint link should be readjusted. Then, repeat the calculation process from steps seven to nine until the requirements of step nine are met.

[0047] Example The aforementioned method for adjusting the flapping vibration of the elastic constant-speed universal joint refers to increasing the radial stiffness of the elastic ball joint and decreasing the axial stiffness of the elastic ball joint connecting rod, so that a portion of the lateral displacement of the constant-speed universal joint is replaced by the axial displacement of the elastic ball joint connecting rod, thereby reducing the lateral vibration of the propeller hub.

[0048] Step 1: Determine the three-arm elastic constant-speed universal joint as the central flapping joint of the propeller hub. Step 2: Establish a simplified calculation formula for the axial stiffness of the elastic ball joint (see Step 2 of the technical solution of this invention). Step 3: Establish a simplified calculation formula for the radial stiffness of the elastic ball joint (see Step 3 of the technical solution of this invention). Step 4: Determine the axial stiffness requirements of the elastic ball cup. The maximum tensile force that the rotor hub can withstand is 15kN. Based on a maximum axial displacement of ≤1mm, the axial stiffness of the elastic ball joint is... =15kN / mm.

[0049] Step 5: Preliminary determination of the main structural dimensions of the elastic ball cup Preliminary determination of the main structural dimensions of the elastic ball cup includes the axial length of the single-layer rubber body of the metal and rubber laminate structure. =20mm, average radius =150mm =1mm and number of layers Four parameters. The selected rubber material has E=1MPa and G=0.1MPa.

[0050] The simplified formula for calculating the axial stiffness of the elastic ball cup according to step two is as follows:

[0051] The formula for calculating the total axial stiffness of an elastic ball joint is:

[0052] Axial stiffness of elastic ball cup This meets the predetermined target requirements.

[0053] Step 6: Calculate the radial stiffness of the elastic ball cup. Based on the four parameters of the metal and rubber laminate structure of the elastic ball cup initially determined in step five, and the elastic modulus of the rubber material E=1MPa, calculate the radial stiffness of the elastic ball cup. : The simplified formula for calculating the radial stiffness of each layer of the elastic body in the elastic spherical cup is as follows:

[0054] The formula for calculating the total radial stiffness of an elastic ball-and-socket bowl is:

[0055] Total radial stiffness of the elastic ball cup .

[0056] Step 7: Preliminary determination of the main structural dimensions of the elastic ball joint connecting rod The main structural dimensions of the elastic ball joint linkage, including the axial length of the single-layer rubber body in the metal and rubber laminate structure, are determined according to the structural space layout requirements. Average radius , and number of layers Four parameters.

[0057] Step 8: Calculate the axial and radial stiffness of the elastic ball joint link. Based on the single-layer rubber body parameters of the metal and rubber laminate structure of the elastic ball joint initially determined in step seven, calculate the axial stiffness of the elastic ball joint. :

[0058] The formula for calculating the total axial stiffness of an elastic ball joint is:

[0059] Axial stiffness of elastic ball joint .

[0060] Step 9: Compare the radial stiffness of the elastic ball cups Axial stiffness of the elastic ball joint link

[0061] Total radial stiffness of the elastic ball cup Axial stiffness of elastic ball joint The axial stiffness of the elastic ball joint is 1 / 5 of the total radial stiffness of the elastic ball cup, satisfying the requirement of at least ≤1 / 2.

[0062] The preliminary design of the flexible ball cup and flexible ball joint was completed by following the steps described above.

Claims

1. A method of adjusting flapping vibration of a rotor hub elastic constant velocity universal joint, characterized by, The adjustment method comprises the following steps: S1, determining to use a three-arm elastic constant velocity universal joint as a central flapping hinge of a hub; S2, establishing a simplified calculation model of axial stiffness and radial stiffness of an elastic bearing assembly in the elastic ball cup and / or the elastic ball hinge connecting rod; S3, determining the axial stiffness requirement of the elastic ball cup based on the maximum tensile force that the hub needs to withstand, the axial stiffness requirement being that the axial displacement of the elastic ball cup under the maximum tensile force is ≤1mm; S4, preliminarily determining the main structure size of the elastic bearing assembly of the elastic ball cup according to the axial stiffness requirement of the elastic ball cup determined in step S3; S5, calculating the radial stiffness (k_(radial-ball cup)) of the elastic ball cup by using the radial stiffness simplified calculation model based on the main structure size determined in step S4; S6, preliminarily determining the main structure size of the elastic bearing assembly of the elastic ball hinge connecting rod according to the structure space arrangement; S7, calculating the axial stiffness (k_(axial-ball hinge)) of the elastic ball hinge connecting rod by using the axial stiffness simplified calculation model based on the main structure size determined in S6; S8, comparing the radial stiffness (k_(radial-ball cup)) of the elastic ball cup with the axial stiffness (k_(axial-ball hinge)) of the elastic ball hinge connecting rod, and adjusting the structure size of the elastic ball hinge connecting rod so that k_(axial-ball hinge) ≤ 1 / 2 k_(radial-ball cup).

2. The method of claim 1, wherein the method further comprises: In the step S2, the axial stiffness simplified calculation formula of each layer of elastic body of the elastic ball hinge is: The total axial stiffness calculation formula of the elastic ball hinge is: Wherein: : represents the axial stiffness of the single rubber body of the metal and rubber laminated structure, unit N / mm; : represents the axial force received by the single rubber body of the metal and rubber laminated structure, unit N; : represents the axial displacement of the single rubber body of the metal and rubber laminated structure after the force is applied, unit: mm; axial length of the single rubber body representing the metal and rubber laminated structure, unit: mm; : represents the radius of the single rubber body of the metal and rubber laminated structure, unit: mm; : represents the thickness of the single rubber body of the metal and rubber laminated structure, unit mm; : represents the single layer rubber body shear modulus of the metal and rubber laminate structure in N / mm2; : denotes the total axial stiffness of the metal and rubber stack-up; : indicates the number of layers of the metal and rubber laminated structure.

3. The method of claim 1, wherein the method further comprises: In the step S2, the radial stiffness simplified calculation formula of each layer of elastic body of the elastic ball cup elastic bearing assembly is: The radial stiffness calculation formula of the elastic ball cup is: Wherein: : denotes the radial stiffness of the single rubber body of the metal and rubber stack structure in N / mm; : represents the radial force received by the single rubber body of the metal and rubber laminated structure, unit N; : represents the radial displacement of the single rubber body of the metal and rubber laminated structure after force, unit: mm; : represents the axial length of the single rubber body of the metal and rubber laminated structure, unit mm; : represents the radius of the single rubber body of the metal and rubber laminated structure, unit mm; : represents the thickness of the single rubber body of the metal and rubber laminated structure, unit mm; : represents the single layer rubber body modulus of the metal and rubber laminate structure in N / mm2; : denotes the total radial stiffness of the metal and rubber stack-up; : indicates the number of layers of the metal and rubber laminated structure.

4. The method of claim 1, wherein the method further comprises: In the step S4, the axial stiffness of the elastic ball cup is determined according to the axial stiffness of the elastic ball cup The main structural dimensions of the elastic ball cup, including the axial length of the single rubber body of the metal and rubber laminated structure , radius , thickness and the number of layers Four parameters.

5. The method of claim 1, wherein the method further comprises: In the step S6, the main structural dimensions of the elastic ball hinge connecting rod include the axial length of the single rubber body of the metal and rubber laminated structure , the radius , the thickness , and the number of layers four parameters.

6. The method of claim 1, wherein the method further comprises: In S8, when k_(axial-ball hinge) ≤ 1 / 2 k_(radial-ball cup) is satisfied, the flapping vibration of the elastic constant velocity universal joint is reduced to 1 / 3 of the maximum value.

7. A rotor hub elastic constant velocity gimbaling device, characterized by, The elastic constant velocity universal joint flapping vibration adjustment method of claim 1-6, Comprise: A main shaft central connecting piece; An elastic ball cup assembly is sleeved on the main shaft central connecting piece; At least three elastic ball hinge connecting rods are connected with the main shaft central connecting piece through the first elastic ball hinge on the inside and connected with the corresponding blade arm through the second elastic ball hinge on the outside; Wherein, the radial stiffness (k_(radial-ball cup)) of the elastic ball cup assembly and the axial stiffness (k_(axial-ball hinge)) of the elastic ball hinge connecting rod satisfy the following relationship: k_(axial-ball hinge) ≤ 1 / 2 k_(radial-ball cup).

8. A flexible constant velocity gimbaling hub for a rotor blade according to claim 7, wherein, The elastic ball cup assembly comprises an upper elastic ball cup and a lower elastic ball cup installed symmetrically up and down.

9. A flexible constant velocity gimbaling hub for a rotor blade according to claim 7, wherein, The elastic ball cup assembly and the elastic bearing assembly in the elastic ball hinge connecting rod are both metal and rubber laminated structures.

10. A flexible constant velocity gimbaling hub for a rotor blade as set forth in claim 7, characterized in that, The axial stiffness of the elastic ball cup assembly is configured to produce an axial displacement of ≤1mm when the hub is subjected to the maximum tensile force.

Images