JP7101054B2 - Anti-vibration structure for unmanned aerial vehicles - Google Patents

Description

The present invention relates to an anti-vibration structure for an unmanned aerial vehicle.

In recent years, the use of small unmanned aerial vehicles, so-called drones, has expanded in fields such as pesticide spraying and aerial photography, and it is expected that the fields of use will continue to expand, such as construction, civil engineering, and transportation.

JP-A-2017-193208A

An unmanned aerial vehicle is a precision device consisting of a combination of flight units and operating devices such as sensors and cameras. However, precision equipment is vulnerable to impact loading. Therefore, when an unmanned aerial vehicle lands, it does not absorb enough shock, causing problems such as overturning and damage. To avoid this, hand-catch landing by humans is recommended, but it is desirable to ensure unmanned landing reliability without humans.

The challenge is to provide an unmanned aerial vehicle anti-vibration structure that can reduce the impact input to the unmanned aerial vehicle during landing of the unmanned aerial vehicle and thus prevent the unmanned aerial vehicle from tipping over or being damaged. do.

The anti-vibration structure of the unmanned aircraft consists of a tubular fixed leg fixed to the main body of the unmanned aircraft and a rod-shaped movable leg connected to the lower end of the fixed leg so as to be slidable in the vertical direction. A disk-shaped rubber foot contact portion provided at the lower end portion of the movable leg portion and grounded at the time of landing of the unmanned aircraft, and attached to the fixed leg portion so as to cover the outer peripheral surface of the fixed leg portion . It is provided with an annular mounting portion and a rubber foot having a thin-walled tubular flexible portion that is provided downward from the mounting portion and exerts a cushioning action by elastically deforming, and the movable leg portion has its own weight. When the unmanned aircraft located at the lower limit of the slide stroke is in flight, a gap is formed between the rubber foot contact portion and the rubber foot to release the lower end portion of the rubber foot to the atmosphere, and the rubber foot contact portion is released. When the unmanned aircraft lands on the ground and the movable leg slides upward, the rubber foot contact portion comes into contact with the rubber foot to elastically deform the flexible portion, and the lower end opening of the rubber foot is opened. An air spring is provided in which the portion is closed and air is sealed in the internal space of the rubber foot, and the cushioning action due to the elastic deformation of the flexible portion and the buffering action due to the compression of the air spring are exerted.

Since the rubber feet are provided on the legs of the unmanned aerial vehicle and the air springs are provided inside the rubber feet, the cushioning action exerted by these rubber feet and the air springs allows input to the unmanned aerial vehicle when the unmanned aerial vehicle lands. It is possible to reduce the impact .

Explanatory drawing of an unmanned aerial vehicle provided with a vibration-proof structure according to an embodiment Cross-sectional perspective view of the anti-vibration structure Cross-sectional view of the anti-vibration structure (A) and (B) are cross-sectional views showing the operating state of the same vibration-proof structure. Cross-sectional perspective view of the anti-vibration structure according to another embodiment Cross-sectional perspective view of the anti-vibration structure according to another embodiment Single cross-sectional view of the rubber feet provided in the anti-vibration structure

As shown in FIG. 1, the unmanned aerial vehicle 1 according to the embodiment is a small unmanned aerial vehicle including a body 11 and legs 21 connected to the body 11. The airframe 11 is equipped with equipment for flying and controlling an unmanned aerial vehicle such as a receiver, a flight controller, a propeller, a motor, and a battery. In the figure, the frame portion 12 of the airframe 11 and the required number of propellers 13 are shown. Shows. On the other hand, the legs 21 stably support the aircraft body 11 in order to protect the aircraft body 11 during takeoff and landing of the unmanned aerial vehicle 1, and the legs 21 having the same structure are provided at three or four locations on the plane of the unmanned aerial vehicle 1. It is provided at a position directly below each propeller 13, for example, over the location. Various operating devices (not shown) such as sensors and cameras are mounted on the machine body 11. The unmanned aerial vehicle 1 is also referred to as an unmanned multicopter or an unmanned rotary wing aircraft, and is also referred to as a so-called drone.

As shown in FIGS. 2 and 3, the leg portion 21 includes a fixed leg portion 31 fixed to the lower surface of the machine body 11, a rubber foot 41 held on the outer periphery of the lower end portion of the fixed leg portion 31, and a fixed leg portion. A movable leg portion 51 connected to the lower end portion of the 31 so as to be slidable in the vertical direction is provided.

The fixed leg portion 31 has a cylindrical shape or a cylinder shape, and is fixed downward to the lower surface of the frame portion 12 of the machine body 11.

The rubber foot 41 is formed into a tubular shape by a predetermined rubber-like elastic body, includes an annular mounting portion 42 for mounting the rubber foot 41 to the fixed leg portion 31, and is directed downward below the mounting portion 42. Further, a thin-walled tubular flexible portion 43 that exerts a cushioning action by elastically deforming during operation (during shock absorption) is integrally provided.

Of these, the mounting portion 42 has a fixed leg portion 31 in which a protrusion-shaped engaging portion 44 provided on the inner peripheral surface thereof engages with a groove-shaped engaging portion 32 provided on the outer peripheral surface of the fixed leg portion 31. However, the mounting means may be press-fitting without engagement, adhesion, or fixing with a fastening band.

The lower end tip portion 45 of the flexible portion 43 has a shape of a constricted tip so that the flexible portion 43 can be easily elastically deformed so as to swell in the outer peripheral direction when a pressing load is applied from below.

The movable leg portion 51 is a rod-shaped part that is slidably inserted into the inner peripheral side of the fixed leg portion 31, and a disk-shaped or piston-shaped engaging portion 52 provided at the upper end thereof is inside the fixed leg portion 31. By engaging with the stepped engaging portion 33 provided on the peripheral surface, the fixed leg portion 31 is prevented from coming off.

Further, at the lower end of the movable leg portion 51, a disk-shaped rubber foot contact portion 53 that is arranged below the rubber foot 41 and is in contact with the rubber foot 41 so as to be in contact with the rubber foot 41 is provided.

The rubber foot contact portion 53 opens the lower end opening 46 of the rubber foot 41 to the atmosphere by forming a vertical gap c between the rubber foot contact portion 53 and the lower end tip portion 45 of the rubber foot 41 as shown in the figure. There is. Further, when the rubber foot contact portion 53 is activated, as shown in FIG. 4A, the rubber foot contact portion 53 contacts the lower end tip portion 45 of the rubber foot 41, closes the lower end opening 46 of the rubber foot 41, and is inside the rubber foot 41. Air (not shown) is sealed in the space 47. Therefore, an air spring 61 made of enclosed air is provided here, and the rubber feet 41 act as an air bag.

In the anti-vibration structure of the unmanned aerial vehicle 1 having the above configuration, the leg portion 21 is not in contact with the ground and the movable leg portion 51 is not in contact with the ground as shown in FIGS. 2 and 3 during the steady state (during the flight of the unmanned aerial vehicle 1). It is located at the lower limit of the slide stroke due to its own weight. Therefore, a gap c is formed between the rubber foot contact portion 53 and the lower end tip portion 45 of the rubber foot 41, and the lower end opening 46 of the rubber foot 41 is open to the atmosphere.

Then, from this state, when the leg portion 21 touches the ground and an impact load is input to the leg portion 21 when the unmanned aircraft 1 tries to land, the movable leg portion 51 receives the impact load and moves upward as shown in FIG. 4 (A). The rubber foot contact portion 53 slides into contact with the lower end tip portion 45 of the rubber foot 41, closes the lower end opening 46 of the rubber foot 41, and encloses air in the internal space 47 of the rubber foot 41.

Further, when an impact load is further input from this state, the movable leg portion 51 slides further upward as shown in FIG. 4B, and the rubber foot contact portion 53 presses the lower end tip portion 45 of the rubber foot 41. The flexible portion 43 of the rubber foot 41 is elastically deformed, and at the same time, the air enclosed in the internal space 47 of the rubber foot 41 is compressed to exert the spring action by the air spring 61.

Therefore, the rubber foot 41 is elastically deformed when the impact load is input to exert a cushioning action, and the air spring 61 is compressed when the impact load is input to exert a buffering action, so that the impact at the time of landing is exerted. It is possible to effectively reduce the load.

When the unmanned aerial vehicle 1 takes off from the state shown in FIG. 4B, the movable leg portion 51 slowly returns to the state shown in FIG. 3 due to its own weight. Therefore, it is possible to prepare for another landing. Further, since the lower end opening 46 of the rubber foot 41 is opened to the atmosphere again by the return motion, even if there is dust that invades the internal space 47 of the rubber foot 41, it is discharged from the lower end opening 46 during flight. be able to.

It is conceivable that the structure of the anti-vibration structure according to the above embodiment may be added or changed as follows.

(1) As shown in FIG. 5, a return spring 71 that returns the movable leg portion 51 to the lower limit position of the slide stroke between the lower end portion of the fixed leg portion 31 and the rubber foot contact portion 53 of the movable leg portion 51. To intervene. According to this, the movable leg portion 51 can be reliably returned to the lower limit position of the slide stroke.

(2) As shown in FIG. 5, the flexible portion 43 of the rubber foot 41 is provided with an air escape hole 48 for discharging a part of the air enclosed in the internal space 47 to the atmosphere side. According to this, the spring characteristics of the air spring 61 can be adjusted according to the size of the holes 48, the number of formations, and the like.

(3) As shown in FIG. 5, a connecting portion 34 made of a female screw or the like for detachably connecting the fixed leg portion 31 to the machine body 11 is provided at the upper end portion of the fixed leg portion 31. According to this, since the leg portion 21 can be replaced, the leg portion 21 can be easily replaced with a leg portion having a vibration-proof structure of another specification.

(4) In the vibration-proof structure according to the above embodiment, if the internal space of the fixed leg portion 31 having a cylindrical shape or a cylinder shape is a closed structure, a second air spring is set here. Therefore, in this case, as shown in FIG. 5, it is conceivable to provide an air escape hole 35 for discharging a part of the air enclosed in the internal space 36 to the atmosphere side on the peripheral surface of the fixed leg portion 31. When the air spring is not set inside the fixed leg portion 31, the internal space 36 is opened to the atmosphere by setting a large opening area of the air escape hole 35.

(5) As shown in FIGS. 6 and 7, a groove shape that causes a pressure loss when air passes through the inner peripheral surface of the mounting portion 42 of the rubber foot 41 that is in airtight contact with the outer peripheral surface of the fixed leg portion 31. The orifice flow path of the above is provided, and the internal space 47 of the rubber foot 41 and the air escape hole 48 provided in the mounting portion 42 of the rubber foot 41 are communicated with each other through the orifice flow path 49. According to this, the cushioning effect can be enhanced by the pressure loss generated in the orifice flow path 49, and the large pressure loss generated by changing the flow path length and the flow path cross-sectional area of the orifice flow path 49. You can adjust the pressure.

In order to set the length of the orifice flow path 49 to be long, it is preferable to form the orifice flow path 49 as a spiral groove as shown in FIG. 7. It is also conceivable that the spiral groove has the shape of a multi-threaded screw, or the forward screw and the reverse screw have a shape that intersects each other.

(6) A bearing (not shown) is interposed between the fixed leg portion 31 and the movable leg portion 51. According to this, the slide stroke of the movable leg portion 51 with respect to the fixed leg portion 31 can be facilitated.

(7) The material of the fixed leg portion 31 and the movable leg portion 51 may be a metal-based material, but in particular, this is a resin-based material. According to this, the weight of the fixed leg portion 31, the movable leg portion 51, and the entire leg portion 21 can be reduced.

1 Unmanned aerial vehicle 11 Main body 12 Frame part 13 Propeller 21 Leg part 31 Fixed leg part 32, 33, 44, 52 Engagement part 34 Connecting part 35, 48 Air escape hole 36, 47 Internal space 41 Rubber foot 42 Mounting part 43 Possible Flexible part 45 Lower end tip 46 Lower end opening 49 orifice flow path 51 Movable leg 53 Rubber foot contact part 61 Air spring 71 Return spring c Gap

Claims (5)

Cylindrical fixed legs fixed to the body of the unmanned aerial vehicle,
A rod-shaped movable leg that is slidably slidable in the vertical direction and connected to the lower end of the fixed leg.
A disk-shaped rubber foot contact portion provided at the lower end of the movable leg portion and grounded at the time of landing of the unmanned aerial vehicle, and a disk-shaped rubber foot contact portion.
An annular mounting portion attached to the fixed leg portion so as to cover the outer peripheral surface of the fixed leg portion, and a thin-walled cylindrical shape provided downward from the mounting portion and elastically deformed to exert a buffering action. A rubber foot with a flexible part and
Equipped with
During flight of the unmanned aerial vehicle in which the movable leg portion is located at the lower limit of the slide stroke due to its own weight, a gap is formed between the rubber foot contact portion and the rubber foot to release the lower end portion of the rubber foot to the atmosphere.
At the time of landing of the unmanned aircraft in which the rubber foot contact portion touches the ground and the movable leg portion slides upward, the rubber foot contact portion comes into contact with the rubber foot to elastically deform the flexible portion, and the flexible portion is elastically deformed. An air spring is provided in which air is sealed in the internal space of the rubber foot by closing the lower end opening of the rubber foot , and exerts a cushioning action due to elastic deformation of the flexible portion and a cushioning action due to compression of the air spring. ,
Anti-vibration structure for unmanned aerial vehicles. In the anti-vibration structure according to claim 1,
A groove-shaped engaging portion is provided on the outer peripheral surface of the fixed leg portion.
The mounting portion is attached to the fixed leg portion by fitting a protrusion-shaped engaging portion provided on the inner peripheral surface thereof to the groove-shaped engaging portion.
The anti-vibration structure of an unmanned aerial vehicle is characterized by that. In the anti-vibration structure according to claim 1 or 2.
The rubber foot is a vibration-proof structure for an unmanned aerial vehicle, characterized in that the rubber foot is provided with an air escape hole that discharges a part of the air enclosed in the internal space to the atmosphere side. In the anti-vibration structure according to claim 3,
The rubber foot is a vibration-proof structure for an unmanned aerial vehicle, characterized in that an orifice flow path that generates a pressure loss is provided between the internal space and the air relief hole. In the anti-vibration structure according to claim 4,
The orifice flow path is a vibration-proof structure for an unmanned aerial vehicle, characterized in that the orifice flow path is provided as a spiral groove on the inner peripheral surface of the rubber foot.

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