KR20230072781A - Dynamic Damping Stopper Assembly for Rotor Hub System - Google Patents

Abstract

In accordance with the present invention, disclosed is a dynamic damping stopper assembly for a rotor hub system, capable of primarily preventing damage to a mast when a stationary rotor is excessively flapped due to a gust of wind while additionally attenuating vibrations of the rotor during flight. In accordance with the present invention, the dynamic damping stopper assembly for a rotor hub system is provided with a plurality of feathering hinge hollow shafts to adjust an angle of attack of a rotor blade, wherein each of the feathering hinge hollow shafts includes a mass body placed to be movable in a horizontal direction and having an end elastically supported by an elastic member, and, when the rotor blade is stopped, each of the mass bodies has a front end kept in tight contact with the outer surface of the mast by pressure from the elastic member, and, when the rotor blade is rotated (flown), each of the mass bodies forms a flapping space for the mast by overcoming the pressure from the elastic member through a centrifugal force and moving within the feathering hinge hollow shafts.

Description

Dynamic Damping Stopper Assembly for Rotor Hub System}

The present invention relates to a dynamic damping stopper assembly, and more particularly, to a dynamic damping stopper assembly of a rotor hub system applicable to a vertical take-off and landing machine such as a helicopter.

In general, the rotor system of a helicopter is a key component that enables helicopter flight together with an engine and a power train, and receives rotational force and pitch control force from a rotor hub/steer to generate lift, thrust, and maneuverability in the helicopter. Controls the rotor blades, the rotor hub system that handles the thrust and moment generated by the rotor blades, and transmits the force necessary for flight to the fuselage, and the thrust and steering force of the helicopter. The main component is a rotor control system (see FIG. 1).

The above-described rotor hub system enables various movements of the rotor blades and bears deformation and loads generated from these movements. As the rotor blades rotate, typical motions generated by air force include flapping motion that moves up and down the rotating surface, lead-lag motion that moves back and forth on the rotating surface, and feathering that moves in the direction of the blade pitch angle. There is a feathering motion (see Figure 2).

Meanwhile, in a conventional vertical take-off and landing aircraft (helicopter), a dissymmetry of lift between the left and right blades occurs due to a difference in wind speed between the right blade and the left blade in forward flight. In other words, lift imbalance is a phenomenon in which the lift generated on the rotating surface of the rotor is not uniform and unbalanced, and the relative speed of the advancing rotor blade and the retreating rotor blade against the relative wind during flight caused by the car.

In order to solve this lift imbalance, a 'rotor blade flapping' function is provided in the conventional rotor system, which allows a motion of moving the blades up and down.

This rotor blade flapping usually has a flapping angle of 8 to 15°, which is a must-have function during flight, but excessive flapping due to gusts on the ground where the rotor rotation is stopped or relatively strong wind generated during takeoff and landing of nearby helicopters. This occurs, resulting in a problem of damage to the master shaft (Mast bumpping). For example, when the rotor head of a helicopter is stationary on the ground, the rotor blade on one side rises excessively due to the downwind caused by the take-off and landing of nearby helicopters, the propulsive wake of large aircraft, or natural gusts. There is a concern that may damage (occurrence of a problem from (a) state to (b) state in FIG. 3).

Therefore, conventionally, various types of flapping stoppers are applied to prevent damage to the mast shaft due to such excessive flapping.

In addition, the conventional flapping stop device requires a dual function of preventing excessive flapping when the rotor is stationary, but permitting free flapping during flight with the rotor rotating.

In other words, according to the continuous development of the rotor system, the need for a dynamic damping stopper that can prevent excessive flapping while the rotor is stationary while primarily on the ground due to gusts of wind and at the same time dampen the vibration of the rotor during flight is also raised. do.

<Prior Document 1>: US Patent Registration US10,988,244 (Announcement Date: April 27, 2021)

The present invention was devised to solve the above problems, and primarily prevents mast damage caused by excessive flapping of the rotor in a stationary state due to gusts of wind, etc., and additionally reduces vibration of the rotor during flight. It is an object to provide a dynamic damping stopper assembly for a damping rotor hub system.

According to one embodiment of the present invention for achieving the above object, a dynamic damping stopper assembly of a rotor hub system having a plurality of feathering hinge hollow shafts for adjusting the angle of attack of a rotor blade, each of the feathering hinges The hollow shaft further includes a mass body disposed to be movable in a horizontal direction and elastically supported by an elastic member at an end portion, and when the rotor blade is stopped, each of the mass bodies is moved by a pressing force of the elastic member to the mass body. The front end is maintained in close contact with the outer surface of the mast, and when the rotor blade rotates (during flight), each of the masses overcomes the pressing force of the elastic member by centrifugal force to move within the feathering hinge hollow shaft A dynamic damping stopper assembly of a rotor hub system forming a flapping space with respect to the mast is provided.

The mass body may be made of a solid round bar made of any one of stainless steel, brass, and Tungsten.

A support section having a part concave inward along an outer circumferential surface may be installed on the mast, and the front end of the mass body may be rounded so as to come into close contact with the concave region of the support section.

When the rotor blade rotates (during flight), the mass moves in the feathering hinge hollow shaft by centrifugal force to form a flapping space with respect to the mast, and the mass body moves in the feathering hinge hollow shaft It may be to damp the vibration transmitted from the rotor while flowing from side to side in (dynamic damping).

In addition, according to another embodiment of the present invention, a dynamic damping stopper assembly of a rotor hub system having a plurality of feathering hinge hollow shafts for adjusting the angle of attack of the rotor blades, wherein each of the feathering hinge hollow shafts has a horizontal It further includes a mass body disposed to be movable in the direction and having an end portion supported by a damper member, and when the rotor blades are stopped, each of the mass bodies is moved so that the front end of the mass body is attached to the outer surface of the mast by the pressing force of the damper member. maintained in close contact, and when the rotor blade rotates (during flight), each of the masses overcomes the pressing force of the damper member by centrifugal force to move within the feathering hinge hollow shaft and flap with respect to the mast A dynamic damping stopper assembly of a rotor hub system forming a space is provided.

The damper member may be an MR damper (Magentto-Rheological Damper) that provides a predetermined damping force by changing the yield stress of the magnetorheological fluid according to the strength of the magnetic field.

According to the present invention, when the rotor is stopped, the rotor in a stopped state is excessively flapped due to a gust of wind to prevent mast damage, and at the same time, dynamic damping control for vibration generated in the rotor through the round rod mass body during flight There are possible effects.

1 is an exploded perspective view showing the main configuration of a conventional helicopter;
2 is a state diagram illustrating various movements of a conventional rotor hub system;
3 is a state diagram showing a state in which a mast is damaged by a gust of wind in a general rotor stop state;
4 is a configuration diagram of a dynamic damping stopper assembly of a rotor hub system according to an embodiment of the present invention;
5 is a configuration diagram showing a state in which a mass body forms a flapping space by switching from a state (stationary state) of FIG. 4 to a flight state;
6 is a comparative state diagram showing the position of a mass body in a rotor stop state and a flight state;
7 is a state diagram in which a dynamic damping stopper assembly of a rotor hub system according to an embodiment of the present invention provides a dynamic damping function during flight, and
8 is a block diagram of a damper device of a dynamic damping stopper assembly of a rotor hub system according to another embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. Prior to this, the terms or words used in this specification and claims should not be construed as being limited to ordinary or dictionary meanings, and the inventor appropriately uses the concept of terms in order to explain his/her invention in the best way. Based on the principle that it can be defined, it should be interpreted as meaning and concept consistent with the technical spirit of the present invention. In addition, unless there is another definition in the technical terms and scientific terms used, they have meanings commonly understood by those of ordinary skill in the art to which this invention belongs. In the following description and accompanying drawings, descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted. The accompanying drawings are provided as examples to sufficiently convey the spirit of the present invention to those skilled in the art. Accordingly, the present invention may be embodied in other forms without being limited to the drawings presented below. Also, like reference numerals denote like elements throughout the specification. It should be noted that like elements in the drawings are indicated by like numerals wherever possible.

<First Embodiment>

In the following embodiments, the dynamic damping stopper assembly of the present invention will be described as an example applied to a seesaw type rotor system of a semi-rigid type, but is not limited thereto and can be applied to various similar rotor systems. . For example, it can be applied to a rotor system equipped with a total head, of course.

Referring to FIG. 4, the dynamic damping stopper assembly of the rotor hub system according to an embodiment of the present invention includes a mast 10 that rotates by providing a driving force, a coupler connected through a rotor blade 20 and a fastener 25 ( 31), a rotor head 60 that flows at a flapping angle of 8 to 15 ° left and right from the flapping hinge point (P ₁ ) at the front end of the mast 10, and a feather connected to both sides of the rotor head 60 A ring hinge hollow shaft 40 and a pair of mass bodies 51 and 52 each elastically supported by an elastic member S ₁ inside the feathering hinge hollow shaft 40 are included.

Specifically, the outer circumferential surface of the feathering hinge hollow shaft 40 is connected to the coupler 31 via a plurality of bearings B ₁ and B ₂ . Accordingly, the feathering angle of the rotor blade 20 may be adjusted by an actuator (not shown) connected to the coupler 31 .

In addition, a support section 11 is installed in the middle of the front end of the mast 10. This support section 11 is provided in a cylindrical shape and forms an inwardly concave area on its outer circumferential surface. In addition, the first mass body 51 and the second mass body 52 are provided with convexly rounded front ends 52a so as to come into contact with the concave area of the support section 11 . Accordingly, as shown in FIG. 4 , the front ends 52a of the first mass body 51 and the second mass body 52 in an elastically supported state are kept in close contact with the concave area of the support section 11, thereby improving support stability. can improve

Meanwhile, the first mass body 51 and the second mass body 52 are movably disposed in the horizontal direction (left and right directions) inside the feathering hinge hollow shaft 40, and the distal end 52b is an elastic member S ₁ supported elastically by Here, these mass bodies 51 and 52 are made of solid metal round rods made of any one of stainless steel, brass, and Tungsten, for example.

In this way, the mass bodies 51 and 52 of the solid metal round bar are, as shown in FIG. 4, when the rotor blades are stopped (ie, the rotor is stopped), each of the mass bodies 51 and 52 is formed by the pressing force of the elastic member S ₁ The front ends 52a of the mass bodies 51 and 52 are kept in close contact with the outer surface (support section) of the mast 10.

Accordingly, it is possible to prevent excessive flapping caused by a gust of wind when the rotor is stopped, leading to damage to the mast. That is, when the rotor is stopped, the mass bodies 51 and 52 are supported on the mast 10 by the spring force of the elastic member S ₁ , thereby suppressing the flapping of the rotor head 60 .

Next, as shown in FIG. 5, when the rotor blade rotates (during flight), each of the mass bodies 51 and 52 overcomes the pressing force of the elastic member S ₁ by centrifugal force within the feathering hinge hollow shaft 40 By moving (that is, moving in the outer radial direction of the rotated rotor blade), a flapping space can be formed with respect to the mast 10 to prepare for lift imbalance.

Here, the weight of the mass bodies 51 and 52 may be determined as a weight corresponding to centrifugal force required according to the number of revolutions of the rotor of the helicopter, the distance from the center of the rotor, and the compressive force of the spring. For example, a soft stop function can be derived by applying an elastic member (spring) that is variable by an elastic force rather than being fixed by a conventional hard stopper device.

That is, during flight, the helicopter's rotor rotates constantly. For example, during takeoff, hovering, cruise, and landing, the rotor speed is constant, and only the power adjustment works to change the angle of attack of the rotor blades. Therefore, since a constant centrifugal force always acts, the required elasticity (spring strength) and compression variation can be easily set.

In FIG. 6, the stopper made up of the mass bodies 51 and 52 overcomes the elastic force of the spring with centrifugal force by the rotation of the rotor during flight from the stationary state (a) of the rotor, thereby losing the role of the stopper and securing the necessary flapping space. (b) is shown.

Referring to FIG. 7 , as described above, the present invention can primarily prevent excessive flapping of a rotor in a stationary state on the ground due to a gust of wind or the like. In addition, according to the present invention, the mass bodies 51 and 52 made of solid metal round rods provide a dynamic damping function on both sides of the rotor hub, so that vibration generated in the rotor during flight can be damped. That is, when excessive vibration such as ground resonance occurs in the rotor momentarily, the mass bodies 51 and 52 shake from side to side within the feathering hinge hollow shaft 40 to change the vibration frequency and avoid resonance. function can also be provided (providing dynamic damping function).

<Second Embodiment>

As another embodiment of the present invention, as shown in FIG. 8, various types of conventional damper devices may be provided in place of the aforementioned elastic member (S1). For example, an MR damper using MR fluid may be applied as a damper device.

Specifically, the MR damper includes a cylinder member 100, a piston member 200, and a magnetic member 300, and a mass body 500 is connected to the front end of the piston member 200.

The cylinder member 100 is a cylindrical member as a whole, and a predetermined space is formed therein, and the MR fluid 102 is filled in the internal space 101. In addition, the cylinder member 100 is made of a magnetic material, and the magnetic field is changed by the movement of the magnetic member 300, thereby providing a predetermined damping force in such a way that the yield stress of the filled MR fluid 102 is changed. .

The MR damper configured as described above can increase the rheological properties, that is, yield stress, of the MR fluid 102 filled in the inner space of the cylinder member 100 by increasing the strength of the magnetic field. Accordingly, the damping force for the mass body 500 can be easily changed through the strength of the magnetic force (ie, damping control more precise than that of the elastic member is possible).

In the above, the present invention has been shown and described with respect to specific embodiments, but the present invention is not limited to the above-described embodiments, and those skilled in the art to which the present invention pertains will find the present invention described in the claims below. Various changes can be made without departing from the gist of the technical idea of the invention.

_P1 : flapping hinge point
10: mast
11: support section
20: rotor blade
25: fastener
31: coupler
40: feathering hinge hollow shaft
51: first mass body
52 second mass body
52a: distal end
52b: distal end
60: rotor head
100: cylinder member
102: MR fluid
200: piston member
300: magnetic member
500: mass body

Claims (6)

A dynamic damping stopper assembly of a rotor hub system having a plurality of feathering hinge hollow shafts for adjusting the angle of attack of the rotor blades,
Further comprising a mass body disposed movably in a horizontal direction inside each of the feathering hinge hollow shafts and having a distal end elastically supported by an elastic member,
When the rotor blades are stopped, the tip of each of the mass bodies is maintained in close contact with the outer surface of the mast by the pressing force of the elastic member,
When the rotor blade rotates (during flight), each of the masses overcomes the pressing force of the elastic member by centrifugal force and moves in the feathering hinge hollow shaft to form a flapping space for the mast. Characterized in that A dynamic damping stopper assembly of a rotor hub system that According to claim 1,
The mass body is a dynamic damping stopper assembly of a rotor hub system, characterized in that made of a solid round bar made of any one of stainless steel, brass, and Tungsten. According to claim 2,
The mast is provided with a support section formed with a portion concave inward along the outer circumferential surface,
The dynamic damping stopper assembly of the rotor hub system, characterized in that the front end of the mass body is rounded to come into close contact with the concave area of the support section. According to claim 2,
When the rotor blade rotates (during flight), the mass moves in the feathering hinge hollow shaft by centrifugal force to form a flapping space with respect to the mast,
The dynamic damping stopper assembly of the rotor hub system, characterized in that the mass moves left and right in the feathering hinge hollow shaft to damp vibration transmitted from the rotor (dynamic damping). A dynamic damping stopper assembly of a rotor hub system having a plurality of feathering hinge hollow shafts for adjusting the angle of attack of the rotor blades,
Further comprising a mass body disposed movably in a horizontal direction inside each of the feathering hinge hollow shafts and having a distal end supported by a damper member,
When the rotor blades are stopped, the front end of each of the mass bodies is maintained in close contact with the outer surface of the mast by the pressing force of the damper member,
When the rotor blade rotates (during flight), each of the masses moves in the feathering hinge hollow shaft by overcoming the pressing force of the damper member by centrifugal force to form a flapping space with respect to the mast. Characterized in that A dynamic damping stopper assembly of a rotor hub system that According to claim 5,
The damper member is a dynamic damping stopper assembly of a rotor hub system, characterized in that a MR damper (Magentto-Rheological Damper) that provides a predetermined damping force by changing the yield stress of the magnetorheological fluid according to the strength of the magnetic field.

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