Pitch limiter for a universal hinge hub and a helicopter

Abstract

The invention discloses a kind of flapping limiting device of universal hinge propeller hub and helicopter, install on rotor shaft, and located the right below of universal hinge propeller hub central piece;The lower part of limiting disc is annular structure, the upper part of limiting disc is provided with limiting cone surface;Limiting disc and limiting cone surface are sleeved outside rotor shaft, and it is gap fit between rotor shaft, can slide up and down along rotor shaft;Self propeller hub central piece is provided with limiting hole, limiting cone surface of limiting disc passes through limiting hole;First support is provided with limiting hole, long pull rod passes through limiting hole, the axial direction of long pull rod is parallel to rotor shaft, the upper end of long pull rod is fixed in the bottom of limiting disc, the lower end of long pull rod is provided with fork-shaped piece;The upper end of short pull rod is assembled on fork-shaped piece by pin shaft, the lower end of short pull rod is installed on fork-shaped piece by pin shaft, which is located in rocker arm upper end;Rocking arm passes through second support, and rocking arm is connected by pivot between second support;The lower end of rocking arm is fixedly installed the pendulum.

Description

Technical Field

[0001] This invention pertains to helicopter rotor hub structure design technology, specifically a flapping limiting device for a universal hinge rotor hub and a helicopter. Background Technology

[0002] Universal hinge rotor hubs, characterized by their small hub radius and compact structure, are now widely used in helicopters. To prevent excessive rotor blade flapping angles and subsequent malfunctions caused by blades colliding with the fuselage, flapping limiting devices must be installed on the rotor hub.

[0003] Traditional helicopter rotor hub flapping limiting devices are divided into upper flapping limiting devices and lower flapping limiting devices. The upper flapping limiting device limits the upward flapping angle of the rotor blades, and the lower flapping limiting device limits the downward flapping angle of the rotor blades. Traditional flapping limiting devices have a single function and cannot perform both upper and lower flapping limiting functions simultaneously. They also have a large number of parts and are relatively heavy. Summary of the Invention

[0004] The purpose of this invention is to provide a flapping limiting device for a universal hinged rotor hub and a helicopter, which solves the problem that the existing technology has a single function and cannot simultaneously perform the functions of upward flapping limiting and downward flapping limiting.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A swing limiting device for a universal hinged propeller hub includes a limiting disc, a long tie rod, a short tie rod, a rocker arm, a second support, a first support, and a pendulum, wherein:

[0007] The flapping limiting device is installed on the rotor shaft and located directly below the central component of the universal joint hub. The lower part of the limiting disc is a ring structure, and the upper part of the limiting disc is provided with a limiting cone surface. The limiting disc and the limiting cone surface are fitted outside the rotor shaft with a clearance fit, allowing them to slide up and down along the rotor shaft. A limiting hole is opened on the central component of the hub, through which the limiting cone surface of the limiting disc passes. The second support and the first support are both installed on the outer wall of the rotor shaft, with the second support located diagonally below the first support. A limiting hole is opened on the first support, through which a long tie rod passes. The axis of the long tie rod is parallel to the rotor shaft, and the upper end of the long tie rod is fixed to the bottom of the limiting disc. A fork-shaped component is provided at the lower end of the long tie rod.

[0008] The upper end of the short pull rod is mounted on the fork-shaped part by a pin, and the lower end of the short pull rod is mounted on the fork-shaped part located at the upper end of the rocker arm by a pin; the rocker arm passes through the second support, and the rocker arm and the second support are connected by a pivot; the pendulum is fixedly installed at the lower end of the rocker arm.

[0009] Furthermore, the inner diameter of the limiting hole is larger than the outer diameter of the limiting disc. When the limiting disc is located inside the limiting hole, the two are in clearance fit.

[0010] Furthermore, the second support has a U-shaped structure, and the rocker arm has a bend in the middle, with the bend being mounted on the second support via a pivot.

[0011] Furthermore, when stationary, both the rocker arm and the short tie rod are tilted relative to the rotor shaft.

[0012] Furthermore, the rocker arm can rotate relative to the second support, the rocker arm to the short tie rod, and the short tie rod to the long tie rod, while the long tie rod can slide up and down relative to the first support.

[0013] Furthermore, rubber or nylon material is wrapped around the outer surface of the limiting disc and the limiting cone for protection.

[0014] Furthermore, when the rotor shaft rotates at high speed, the pendulum moves away from the rotor shaft under the action of centrifugal force, driving the short tie rod to rotate through the rocker arm. The short tie rod then drives the long tie rod and the limiting disc to slide downwards. The central component of the universal joint rotor hub is not fixed to the rotor shaft. When the rotor flaps, the central component of the rotor hub will tilt relative to the rotor shaft in the flapping direction. When the flapping angle of the central component of the rotor hub exceeds the limit angle, the limiting hole on the central component of the hub collides with the limiting cone surface of the limiting disc, thus achieving the purpose of limiting the flapping motion while the rotor is rotating.

[0015] Furthermore, when the rotor shaft speed decreases or stops, the centrifugal load decreases, and the pendulum moves towards the rotor shaft under the action of gravity. This causes the short tie rod to rotate via the rocker arm, and the short tie rod causes the long tie rod and the limiting disk to slide upwards. The limiting hole of the rotor hub center component makes clearance contact with the outer ring surface of the limiting disk, thus achieving the purpose of limiting the flapping motion when the rotor is stopped.

[0016] A helicopter, wherein the aforementioned flapping limiter is mounted on the universal joint hub of the helicopter.

[0017] Compared with the prior art, the present invention has the following technical features:

[0018] 1. The present invention can simultaneously limit the upward and downward flapping angles of the rotor hub, and can maintain the flapping limiting function simultaneously when the rotor hub is rotating and stationary.

[0019] 2. The waving limiter has fewer parts and a compact structure, making it suitable for helicopter rotor hubs with high lightweight requirements.

[0020] 3. It uses fewer moving joints, resulting in lower design and manufacturing costs, higher reliability, and better maintainability. Attached Figure Description

[0021] Figure 1 This is a schematic diagram illustrating the working principle of the waving limiting device in a stopped state.

[0022] Figure 2 This is a schematic diagram illustrating the working principle of the waving limiting device in a rotating state.

[0023] The numbers in the diagram are as follows: 1 rotor shaft, 2 limiting disc, 3 long tie rod, 4 short tie rod, 5 rocker arm, 6 second support, 7 first support, 8 pendulum, 9 rotor hub center component, 10 limiting hole, 11 limiting cone surface. Detailed Implementation

[0024] This invention provides a flapping limiter for a universal joint rotor hub, employing a centrifugal pendulum limiting principle. It can simultaneously limit the upward and downward flapping angles of the rotor hub in both rotating and stationary states. This invention has fewer parts and fewer moving joints, resulting in better reliability and maintainability, and effectively reducing helicopter design and manufacturing costs.

[0025] See appendix Figure 1 and 2 The present invention provides a swing limiting device for a universal hinged propeller hub, including a limiting disc 2, a long tie rod 3, a short tie rod 4, a rocker arm 5, a second support 6, a first support 7, and a pendulum 8.

[0026] The waving limiting device 1 is installed on the rotor shaft 1 and is located directly below the central component 9 of the universal joint hub; the lower part of the limiting disk 2 is a ring structure, and the upper part of the limiting disk 2 is provided with a limiting cone surface 11; the limiting disk 2 and the limiting cone surface 11 are fitted on the outside of the rotor shaft 1, and there is a clearance fit between them, allowing them to slide up and down on the rotor shaft 1; a limiting hole 10 is opened on the central component 9 of the hub, and the limiting cone surface 11 of the limiting disk 2 passes through the limiting hole 10; the second support 6 and the first support 7 are both installed on the outer wall of the rotor shaft 1, and the second support 6 is located diagonally below the first support 7; a limiting hole is opened on the first support 7, and a long tie rod 3 passes through the limiting hole. The axis of the long tie rod 3 is parallel to the rotor shaft 1, the upper end of the long tie rod 3 is fixed to the bottom of the limiting disk 2, and the lower end of the long tie rod 3 is provided with a fork-shaped component. The inner diameter of the limiting hole 10 is larger than the outer diameter of the limiting disk 2. When the limiting disk 2 is located inside the limiting hole 10, the two are in clearance fit.

[0027] The upper end of the short pull rod 4 is mounted on the fork-shaped part by a pin, and the lower end of the short pull rod 4 is mounted on the fork-shaped part located at the upper end of the rocker arm 5 by a pin; the rocker arm 5 passes through the second support 6, which has a U-shaped structure, and the rocker arm 5 and the second support 6 are connected by a pivot; the pendulum 8 is fixedly installed at the lower end of the rocker arm 5.

[0028] The rocker arm 5 has a bend in the middle, and the bend is mounted on the second support 6 via a pivot.

[0029] When stationary, both rocker arm 5 and short tie rod 4 are tilted towards rotor shaft 1.

[0030] The rocker arm 5 can rotate relative to the second support 6, the rocker arm 5 can rotate relative to the short tie rod 4, and the short tie rod 4 can rotate relative to the long tie rod 3. The long tie rod 3 can slide up and down relative to the first support 7.

[0031] The waving motion limiting device 1 uses the centrifugal pendulum motion limiting principle:

[0032] When the rotor shaft 1 rotates at high speed, the pendulum 8 moves away from the rotor shaft 1 under the action of centrifugal force. It drives the short tie rod 4 to rotate through the rocker arm 5. The short tie rod 4 drives the long tie rod 3 and the limiting disk 2 to slide downward. The characteristic of the universal joint hub is that the central part 9 of the rotor hub is not fixed to the rotor shaft 1. When the rotor flaps, the central part 9 of the rotor hub will tilt relative to the rotor shaft 1 in the flapping direction. Therefore, when the flapping angle of the central part 9 of the rotor hub exceeds the limit angle, the limiting hole 10 on the central part 9 of the hub collidees with the limiting cone surface 11 of the limiting disk 2, so as to achieve the purpose of limiting the flapping motion when the rotor is rotating.

[0033] When the rotor shaft 1 speed decreases or stops, the centrifugal load decreases, and the pendulum 8 moves towards the rotor shaft 1 under the action of gravity. It drives the short tie rod 4 to rotate through the rocker arm 5. The short tie rod 4 drives the long tie rod 3 and the limiting disk 2 to slide upward. The limiting hole 10 of the rotor hub center part 9 is in clearance contact with the outer ring surface of the limiting disk 2 to achieve the purpose of limiting the flapping movement when the rotor is stopped.

[0034] Considering that the swing limiting device 1 needs to contact or collide with the central part of the propeller hub 9 when limiting the swing angle, in order to prevent damage to the central part of the propeller hub 9, a layer of rubber or nylon material can be wrapped around the outer surface of the limiting disc 2 and the limiting cone surface 11 for protection.

[0035] The specific size of the limiting hole is determined according to the swing angle limiting requirements; the larger the swing angle, the greater the difference between the inner diameter of the limiting hole and the outer diameter of the limiting disk 2; and vice versa. The above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A flapping limiting device for a universal hinged propeller hub, characterized in that, It includes a limiting disc (2), a long tie rod (3), a short tie rod (4), a rocker arm (5), a second support (6), a first support (7), and a pendulum (8), wherein: The waving limiting device is installed on the rotor shaft (1) and located directly below the central component (9) of the universal joint hub; the lower part of the limiting disk (2) is a ring structure, and the upper part of the limiting disk (2) is provided with a limiting cone surface (11); the limiting disk (2) and the limiting cone surface (11) are fitted outside the rotor shaft (1) and are clearance-fitted with the rotor shaft (1), and can slide up and down along the rotor shaft (1); a limiting hole (10) is opened on the central component (9) of the hub, and the limiting disk (2) The limiting cone surface (11) passes through the limiting hole (10); the second support (6) and the first support (7) are both installed on the outer wall of the rotor shaft (1), the second support (6) is located diagonally below the first support (7); the first support (7) has a limiting hole, the long tie rod (3) passes through the limiting hole, the axial direction of the long tie rod (3) is parallel to the rotor shaft (1), the upper end of the long tie rod (3) is fixed to the bottom of the limiting plate (2), and the lower end of the long tie rod (3) is provided with a fork-shaped part; The upper end of the short pull rod (4) is mounted on the fork-shaped part by a pin, and the lower end of the short pull rod (4) is mounted on the fork-shaped part located at the upper end of the rocker arm (5) by a pin; the rocker arm (5) passes through the second support (6), and the rocker arm (5) and the second support (6) are connected by a pivot; the pendulum (8) is fixedly mounted at the lower end of the rocker arm (5); the middle part of the rocker arm (5) is bent, and the bent position is mounted on the second support (6) by a pivot; When the rotor shaft (1) rotates at high speed, the pendulum (8) moves away from the rotor shaft (1) under the action of centrifugal force. It drives the short tie rod (4) to rotate through the rocker arm (5). The short tie rod (4) drives the long tie rod (3) and the limiting disk (2) to slide downward. The rotor hub center part (9) of the universal hinge rotor hub is not fixed to the rotor shaft (1). When the rotor flaps, the rotor hub center part (9) will tilt relative to the rotor shaft (1) in the flapping direction. When the flapping angle of the rotor hub center part (9) exceeds the limit angle, the limiting hole (10) on the hub center part (9) collides with the limiting cone surface (11) of the limiting disk (2) to achieve the purpose of limiting the flapping motion in the rotor rotation state. When the rotor shaft (1) speed decreases or stops, the centrifugal load decreases, and the pendulum (8) moves towards the rotor shaft (1) under the action of gravity. It drives the short tie rod (4) to rotate through the rocker arm (5), and the short tie rod (4) drives the long tie rod (3) and the limiting disk (2) to slide upward. The limiting hole (10) of the rotor hub center part (9) and the outer ring surface of the limiting disk (2) are in clearance contact to achieve the purpose of limiting the flapping movement when the rotor stops.

2. The flapping limiting device for the universal joint propeller hub according to claim 1, characterized in that, The inner diameter of the limiting hole (10) is larger than the outer diameter of the limiting disk (2). When the limiting disk (2) is located inside the limiting hole (10), the two are in clearance fit.

3. The flapping limiting device for the universal hinged propeller hub according to claim 1, characterized in that, The second support (6) is a U-shaped structure.

4. The flapping limiting device for the universal hinged propeller hub according to claim 1, characterized in that, When stationary, the rocker arm (5) and the short tie rod (4) are both tilted toward the rotor shaft (1).

5. The flapping limiting device for the universal joint propeller hub according to claim 1, characterized in that, The rocker arm (5) can rotate relative to the second support (6), the rocker arm (5) can rotate relative to the short tie rod (4), and the short tie rod (4) can rotate relative to the long tie rod (3). The long tie rod (3) can slide up and down relative to the first support (7).

6. The flapping limiting device for the universal joint propeller hub according to claim 1, characterized in that, Rubber or nylon material is wrapped around the outer surface of the limiting disc (2) and the limiting cone surface (11) for protection.

7. A helicopter, characterized in that, The helicopter is equipped with a flapping limiter according to any one of claims 1-6 on its universal joint rotor hub.

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