Self-adaptive torsion damper and aircraft

Abstract

The invention belongs to the field of vibration control, and relates to a self-adaptive torsion damper and an aircraft which are used for variable-speed helicopter rotors, torque transmission paths and transmission systems, and the damper is characterized in that the inner wall of an outer ring is connected with the outer wall of an inner ring of a center hole through N groups of centrifugal grooves; the center ring is installed on the rotating component through the center hole inner ring and rotates together with the rotating component. N is a natural number greater than or equal to 2; n groups of first-stage springs, N groups of second-stage springs, N groups of second-stage mass blocks and N groups of friction mass block assemblies are arranged in the N groups of centrifugal grooves respectively; one end of the secondary spring is connected with the outer wall of the inner ring of the center hole, and the other end of the secondary spring is connected with the inner side of the mass block; the outer ring is provided with an annular groove penetrating through the inner end face and the outer end face of the outer ring, and the inner friction ring is arranged in the annular groove, connected with the outer ring through a sliding unit and rotates along the annular groove in a sliding mode.

Description

Technical Field

[0001] The invention belongs to the field of vibration control and relates to an adaptive torsional vibration damper for a variable speed helicopter rotor, a torque transmission path and a transmission system and an aircraft. Background Art

[0002] Traditional helicopter rotors are usually designed with a fixed speed. With the development of electric drive rotor technology and the emergence of new helicopter configurations, variable speed technology has gradually been studied and applied in the field of new rotor design. The use of variable speed rotor technology can configure the overall lift-to-drag ratio of the rotor under different flight conditions, improve the helicopter's climbing performance, load, ceiling, etc., and can greatly improve the rotor performance and endurance, and effectively reduce the rotor aerodynamic noise. Variable speed rotor technology can also improve the economic efficiency of helicopters by increasing the life of helicopters, engines (motors), and transmission systems.

[0003] The vibration characteristics of traditional helicopters are the superposition of typical KNΩ periodic vibration and random vibration. At the same time, the rotor, as the main lift system, is the main source of vibration load, especially the body vibration caused by NΩ vibration load related to the number of rotor blades and rotation speed. Within the frequency range of interest of the helicopter vibration prediction and control research, it has become a key technology that seriously affects the performance and function of the helicopter. The vibration load of the rotor synthesizes six components of force and torque on the hub, which is transmitted to the body through the transmission system and other transmission paths, and is the main source of vibration that causes the overall vibration of the helicopter.

[0004] However, the result of the variable speed of the helicopter rotor is that its main vibration frequency changes. At the same time, the rotor whose speed changes in real time will be affected by the speed change rate at the moment of speed change, which makes the excitation frequency of the variable speed rotor helicopter not fixed and has the influence of torsional vibration in the torsional direction. The traditional fixed frequency damper can no longer meet the demand for vibration control of variable speed rotor helicopters. Summary of the invention

[0005] The purpose of the present invention is: to solve at least one of the above-mentioned technical problems, the present invention provides an adaptive torsional vibration damper and an aircraft for a variable speed helicopter rotor, a torque transmission path and a transmission system, which can suppress the vibration load in the torsional direction during the speed change and the speed change process, and at the same time have the vibration absorption effect of the plane vibration load perpendicular to the axis.

[0006] In order to achieve the above tasks, the present invention adopts the following technical solutions:

[0007] An adaptive torsional vibration damper comprises: a center ring, a primary spring, a secondary spring, a secondary mass block, a friction mass block assembly and an inner friction ring;

[0008] The center ring comprises: an outer ring, a concentric inner ring of the center hole and N groups of centrifugal grooves; the inner wall of the outer ring is connected to the outer wall of the inner ring of the center hole through the N groups of centrifugal grooves; the center ring is installed on the rotating component through the inner ring of the center hole and rotates together with the rotating component; N is a natural number greater than or equal to 2;

[0009] There are N groups of the primary spring, the secondary spring, the secondary mass block, and the friction mass block assembly, which are respectively arranged in the N groups of centrifugal grooves; one end of the secondary spring is connected to the outer wall of the inner ring of the center hole, and the other end is connected to the inner side of the mass block, the outer side of the mass block is connected to one end of the primary spring, and the other end of the primary spring is connected to the friction mass block assembly;

[0010] The outer ring is provided with an annular groove penetrating the inner and outer end surfaces of the outer ring, the inner friction ring is arranged in the annular groove, the inner friction ring is connected to the outer ring through a sliding unit and rotates along the annular groove in a sliding manner.

[0011] Furthermore, a slide rail is provided in the centrifugal groove, and the secondary mass block moves radially along the slide rail under the action of centrifugal force.

[0012] Furthermore, the N groups of centrifugal grooves are evenly distributed along the circumference to avoid eccentricity.

[0013] Furthermore, N is 4.

[0014] Furthermore, the sliding unit is a ball bearing, which reduces the friction between the inner friction ring and the outer ring as much as possible.

[0015] Furthermore, the inner surface of the inner friction ring is formed of a wear-resistant material to form a wear-resistant surface; the wear-resistant material can be high manganese steel, wear-resistant high chromium cast iron, wear-resistant alloy steel, which reduces friction loss and heat generation.

[0016] The primary spring is always in a compressed state, and the primary spring presses the friction mass block assembly onto the inner friction ring, and the friction mass block assembly and the inner friction ring are in friction contact, thereby reducing the nonlinear phenomenon of the primary spring changing from a compressed state to a stretched state.

[0017] Furthermore, the friction mass block assembly includes a friction plate and a sliding frame; the sliding frame is connected to a primary spring, the outer side of the sliding frame is connected to the friction plate, and the friction plate is in friction contact with the inner friction ring. The friction plate is made of powder metallurgy material and has good wear resistance.

[0018] Furthermore, the stiffness k1 of the primary spring, the stiffness k2 of the secondary spring and the mass m of the secondary mass block are calculated as follows:

[0019]

[0020] N0 is the initial pressure between the friction plate and the inner friction ring;

[0021] Ω is the speed of the rotating part at a uniform speed;

[0022] J is the moment of inertia of the inner friction ring;

[0023] a w is the angular acceleration of the rotating part;

[0024] F 外 The inner friction ring is subjected to external damping force;

[0025] f is the friction force between the friction plate and the inner friction ring;

[0026] f max is the maximum static friction between the friction plate and the inner friction ring;

[0027] m1 and m2 are the masses of the friction mass assembly and the secondary mass block, respectively;

[0028] r2 and R are the initial radii of the friction mass block assembly and the secondary mass block.

[0029] An aircraft comprises the adaptive torsional vibration damper.

[0030] Beneficial effects: The adaptive torsional vibration damper, including a center ring, an inner friction ring, a secondary mass block, a friction mass block assembly, a secondary spring, a primary spring, and a ball bearing, is installed on the shaft system of a variable speed helicopter rotor, a torque transmission path, and a transmission system to achieve the suppression of vibration loads in the torsional direction during changes in speed and speed, and at the same time has the effect of absorbing vibration loads in the plane perpendicular to the axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is the principle diagram of adaptive torsional vibration damper;

[0032] Figure 2 It is an axonometric view of the adaptive torsional vibration damper;

[0033] Figure 3 is a cross-sectional view of the adaptive torsional vibration damper along the center plane of the inner friction ring;

[0034] Figure 4 It is the AA-plane cross-sectional view of the adaptive torsional vibration damper;

[0035] In the figure, 100 is a center ring, 101 is a center hole, 102 is a centrifugal groove, 103 is an outer groove, 200 is an inner friction ring, 300 is a secondary mass block, 400 is a friction mass block assembly, 401 is a friction plate, 402 is a slide frame, 500 is a secondary spring, 600 is a primary spring, 700 is a ball bearing, 701 is an outer ring, 702 is a ball, and 703 is an inner ring. DETAILED DESCRIPTION

[0036] A torsional vibration damper with speed adaptation installed on a shaft system such as a rotor hub or a transmission system. It is mainly composed of a center ring, an inner friction ring, a secondary mass block, a friction mass block assembly, a secondary spring, a primary spring, and a ball bearing. The ball bearing can also be implemented by a plane bearing such as a roller bearing.

[0037] The center ring has a centrifugal groove, a center hole and an outer groove, and a secondary spring, a secondary mass block, a primary spring and a friction mass block assembly are installed in the centrifugal groove from the center hole to the outer groove. The secondary mass block moves radially in the centrifugal groove under the action of centrifugal force. The friction mass block assembly can move in the groove along the radius direction of the center ring.

[0038] A ball bearing is installed at the outer groove of the center ring, and the inner ring of the ball bearing is connected to the outer groove of the center ring. The outer ring of the ball bearing is connected to the inner friction ring, so that the inner friction ring can rotate around the center ring.

[0039] The inner surface of the inner friction ring is made of wear-resistant materials such as high manganese steel, wear-resistant high chromium cast iron, wear-resistant alloy steel, etc. When the center ring and the inner friction ring rotate relative to each other, the wear-resistant surface of the inner friction ring will move relative to the friction mass block assembly to generate sliding friction.

[0040] The friction mass block assembly is composed of a friction plate and a sliding frame; the friction plate is made of powder metallurgy material. The friction plate is bonded to the outer surface of the sliding frame along the radial direction. The sliding frame is connected to a primary spring, and the primary spring is initially in a compressed state. The outer surface of the friction plate contacts the wear-resistant surface of the inner friction ring.

[0041] The adaptive torsional vibration damper is connected to the rotating component through the center hole of the center ring and is fixedly connected to the rotating component and can rotate together with the rotating component.

[0042] The key points of the present invention are:

[0043] The traditional torsional vibration reduction system or helicopter hub vibration absorption system is designed for a specific rotational speed frequency, and its optimal vibration isolation frequency is single and cannot simultaneously meet the vibration reduction requirements in the torsional direction and in the plane. The adaptive torsional vibration damper device of the present invention has the vibration reduction capability in the rotational plane and in the torsional direction. The planar spring oscillator system composed of a primary spring, a secondary spring and a secondary mass block can reduce the vibration response of the rotor rotation plane. The friction system in the torsional direction composed of a friction mass block assembly and an inner friction ring can effectively reduce the torsional vibration caused by the speed change process during the speed change process. Due to the influence of centrifugation, the centrifugal force of the spring oscillator system is different under different speeds, thereby achieving different positive pressures on the contact surface of the friction mass block assembly and the inner friction ring, thereby adapting to the vibration reduction requirements under different speeds and ensuring the vibration reduction requirements of the variable speed rotor helicopter within the full envelope flight range.

[0044] A characteristic of the adaptive torsional vibration damper is that the plane vibration reduction system is composed of a primary spring, a secondary spring and a secondary mass block. This design makes the present invention similar to a spring oscillator vibration absorption system in the plane, and can reduce the vibration signal in the plane of the rotor shaft system. At the same time, due to the relative friction between the friction mass block assembly and the inner friction ring, when the vibration absorption system moves, it can also provide a certain friction damping to increase the dissipation of vibration energy. And the initial pressure of the friction mass block assembly and the inner friction ring is constant. As the plane excitation vibration increases, the contact pressure between the friction mass block assembly and the inner friction ring increases, the equivalent friction damping also increases, and the vibration absorption capacity is stronger, that is, it can better adapt to the changes in the plane vibration excitation, and ensure that the vibration of the rotor shaft system in the plane is at a low level.

[0045] Another characteristic of the adaptive torsional vibration damper is that the torsional vibration damping system is composed of a spring system, a friction mass block assembly, a center ring, a ball bearing and an inner friction ring. This design enables the present invention to reduce the torsional vibration caused by the change of torsional acceleration in the torsional direction. When the speed of the mounting shaft system changes, the speed direction will produce speed acceleration and deceleration, causing the center ring and the inner friction ring to move relative to each other. This movement will also cause the inner friction ring and the friction mass block assembly to move relative to each other, thereby providing friction damping in this direction, consuming the torsional vibration caused by the change of speed in the torsional direction, and improving the stability in the torsional direction.

[0046] The working principle of the present invention is as follows:

[0047] When the shafting of the variable speed helicopter rotor, torque transmission path or transmission system vibrates perpendicular to the axis, the adaptive torsional vibration damper installed on the shafting

[0048] Assuming that the mass of the spring and other damping of the system can be ignored, the friction surface of the friction plate fits tightly and the wear state of the friction plate is not considered, there are the following four states.

[0049] State 1: Static state

[0050] Since the spring is in a pre-compressed state, there is a pressure between the friction plate and the inner friction ring: N0

[0051] State 2: The axis system rotates at a constant speed

[0052] Assume that the rotation speed of the shaft system is Ω, and the external damping force on the inner friction ring is F. 外 , there are two possible situations:

[0053] 2.1 There is no relative motion between the center ring and the inner friction ring

[0054] That is, F 外 =f≤f max

[0055] At this time, the centrifugal force on m2 is

[0056]

[0057] 2.2 Relative motion between the center ring and the inner friction ring

[0058] At this time, the centrifugal forces on m1 and m2 are

[0059]

[0060]

[0061] At this time, the friction plate is subjected to pressure changes and sliding friction force is

[0062] ΔN=F 1离 +k1L2

[0063] f=μ(N0+ΔN)=μ(N0+4m1Ω 2 Rπ 2 +k1L2)

[0064] State 3: shaft system acceleration and deceleration rotation

[0065] At this time, the friction increment required for the inner friction ring to maintain relative stillness with the center ring is

[0066] ΔF=Ja w / R

[0067] 3.1 There is no relative motion between the center ring and the inner friction ring

[0068] That is, F 外 +ΔF=f≤f max

[0069] At this time, the centrifugal force on m2 is

[0070]

[0071] 3.2 Relative motion between the center ring and the inner friction ring

[0072] At this time, the centrifugal forces on m1 and m2 are

[0073]

[0074]

[0075] At this time, the friction plate is subjected to pressure changes and sliding friction force is

[0076] ΔN=F 1离 +k1L2

[0077] f=μ(N0+ΔN)=μ(N0+4m1(Ω+ΔΩ) 2 Rπ 2 +k1L2)

[0078] By solving the above equations, we can obtain the centrifugal force and friction force on each mass under different states of rotation around the central axis.

[0079] State 4: Vibration perpendicular to the axis plane

[0080] When the adaptive torsional vibration damper is arranged symmetrically,

[0081] F w =(k1+k2)L2 / 2

[0082] And the vibration absorption frequency of the vibration absorption system at this time is

[0083]

[0084] In summary:

[0085] In order to achieve the highest efficiency of the shock absorber, theoretically, the maximum static friction is achieved when rotating at the rated speed. At this time, the shock absorber has the best vibration reduction effect on the acceleration and deceleration of the shaft system. That is:

[0086] f max =μ(N0+ΔN)=μ(N0+4m1Ω 2 Rπ 2 +k1L2)

[0087] In view of the vibration reduction requirements of the rotating plane of the rotor system, the vibration reduction required in the rotating coordinate system is Ω, and the secondary mass block of the torsional vibration damper is:

[0088] m2=(k1+k2)Ω2

[0089] In order to achieve coordinated spring motion, the spring stiffness is selected to be the same, and the design parameters are:

[0090]

[0091] N0 and ΔN are the initial pressure and its variation between the friction plate and the inner friction ring

[0092] Ω and ΔΩ are the speed and speed change of the uniform rotation of the shaft system

[0093] J is the moment of inertia of the inner friction ring

[0094] a w The acceleration and deceleration of the shaft rotation angle

[0095] F 外 The inner friction ring is subjected to external damping force

[0096] f is the friction force between the friction plate and the inner friction ring

[0097] f max is the maximum static friction between the friction plate and the inner friction ring

[0098] m1 and m2 are the masses of the friction mass block assembly and the secondary mass block respectively

[0099] F 1离 、F 2离 The centrifugal forces of the friction mass block assembly and the secondary mass block are

[0100] F w The plane vibration load of the vertical axis

[0101] r2, R is the initial radius of the friction mass block assembly and the secondary mass block

[0102] L2 is the displacement of the secondary mass block under the action of centrifugal force

[0103] k1 and k2 are the stiffness of the primary spring and the secondary spring respectively

[0104] ω is the vibration absorption frequency of the plane motion vibration absorption system

[0105] μ is the friction coefficient between the friction plate and the inner friction ring

[0106] v1 and v2 are the linear velocities of the friction mass assembly and the secondary mass block rotating around the center respectively

[0107] r The radius of the position of the secondary mass block during the rotation process

[0108] ΔF is the friction increment required for the inner friction ring to maintain relative stillness with the center ring.

[0109] π is the ratio of a circle to its diameter

[0110] The advantages of the present invention are:

[0111] The adaptive torsional vibration damper can provide different sizes of friction damping force according to the change of shaft system speed to adapt to the vibration reduction requirements of the variable speed shaft system: first, the vibration reduction system in the torsional direction composed of the center ring, the inner friction ring and the friction mass block assembly can reduce the vibration in the torsional direction and the excitation of the vibration caused by acceleration and deceleration. At the same time, due to the centrifugal effect, the spring system where the secondary mass block is located can adapt to the requirements for friction damping force under different speeds and speed change rates; second, the spring oscillator system composed of the secondary mass block and the spring can not only meet the requirements of the friction plate for the change of the positive pressure of the friction plate under different speeds, but also absorb the vibration of the shaft system in the plane direction; third, the pre-stress spring can provide the elastic deformation requirements of the mass spring system in the vibration absorption process, and can also ensure that the friction plate is always in a pressure state, and when the speed changes, under the action of centrifugal force, the equilibrium position of the secondary mass block is changed.

Claims

1. An adaptive torsional vibration damper, characterized in that: The shock absorber comprises: a center ring, a primary spring, a secondary spring, a secondary mass block, a friction mass block assembly and an inner friction ring; The center ring comprises: an outer ring, a concentric inner ring of the center hole and N groups of centrifugal grooves; the inner wall of the outer ring is connected to the outer wall of the inner ring of the center hole through the N groups of centrifugal grooves; the center ring is installed on the rotating component through the inner ring of the center hole and rotates together with the rotating component; N is a natural number greater than or equal to 2; There are N groups of the primary spring, the secondary spring, the secondary mass block, and the friction mass block assembly, which are respectively arranged in the N groups of centrifugal grooves; one end of the secondary spring is connected to the outer wall of the inner ring of the center hole, and the other end is connected to the inner side of the mass block, the outer side of the mass block is connected to one end of the primary spring, and the other end of the primary spring is connected to the friction mass block assembly; The outer ring is provided with an annular groove penetrating the inner and outer end surfaces of the outer ring, the inner friction ring is arranged in the annular groove, the inner friction ring is connected to the outer ring through a sliding unit and rotates along the annular groove in a sliding manner.

2. The shock absorber according to claim 1, characterized in that: A slide rail is arranged in the centrifugal groove, and the secondary mass block moves radially along the slide rail under the action of centrifugal force.

3. The shock absorber according to claim 2, characterized in that: N groups of centrifugal grooves are evenly distributed along the circumferential direction.

4. The vibration absorber according to claim 3, characterized in that: N is 4.

5. The vibration absorber according to claim 4, characterized in that: The sliding unit is a ball bearing.

6. The shock absorber according to claim 5, characterized in that: The inner surface of the inner friction ring is formed into a wear-resistant surface by wear-resistant material; The primary spring is always in a compressed state, and the primary spring presses the friction mass block assembly onto the inner friction ring, so that the friction mass block assembly is in friction contact with the inner friction ring.

7. The vibration absorber according to claim 6, characterized in that: The friction mass block assembly comprises a friction plate and a sliding frame; the sliding frame is connected to a primary spring, the outer side of the sliding frame is connected to the friction plate, and the friction plate is in friction contact with an inner friction ring.

8. The vibration absorber according to claim 7, characterized in that: The calculation formulas for the stiffness k1 of the primary spring, the stiffness k2 of the secondary spring and the mass m of the secondary mass block are as follows: N0 is the initial pressure between the friction plate and the inner friction ring; Ω is the speed of the rotating part at a uniform speed; J is the moment of inertia of the inner friction ring; a w is the angular acceleration of the rotating part; F 外 The inner friction ring is subjected to external damping force; f is the friction force between the friction plate and the inner friction ring; f max is the maximum static friction between the friction plate and the inner friction ring; m1 and m2 are the masses of the friction mass assembly and the secondary mass block, respectively; r2 and R are the initial radii of the friction mass block assembly and the secondary mass block.

9. An aircraft, characterized in that: The aircraft comprises the adaptive torsional vibration damper according to any one of claims 1-8.

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