CN110958975A - Leg portion, leg portion unit and unmanned vehicles - Google Patents

Leg portion, leg portion unit and unmanned vehicles Download PDF

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Publication number
CN110958975A
CN110958975A CN201880049416.9A CN201880049416A CN110958975A CN 110958975 A CN110958975 A CN 110958975A CN 201880049416 A CN201880049416 A CN 201880049416A CN 110958975 A CN110958975 A CN 110958975A
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China
Prior art keywords
leg
load
reinforcing member
main body
portions
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Granted
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CN201880049416.9A
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Chinese (zh)
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CN110958975B (en
Inventor
四宫隆
吉原正典
米原慧纪
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Yamaha Motor Co Ltd
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Yamaha Motor Co Ltd
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Publication of CN110958975A publication Critical patent/CN110958975A/en
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B64AIRCRAFT; AVIATION; COSMONAUTICS
    • B64CAEROPLANES; HELICOPTERS
    • B64C25/00Alighting gear
    • B64C25/32Alighting gear characterised by elements which contact the ground or similar surface 
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B64AIRCRAFT; AVIATION; COSMONAUTICS
    • B64DEQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
    • B64D1/00Dropping, ejecting, releasing, or receiving articles, liquids, or the like, in flight
    • B64D1/16Dropping or releasing powdered, liquid, or gaseous matter, e.g. for fire-fighting
    • B64D1/18Dropping or releasing powdered, liquid, or gaseous matter, e.g. for fire-fighting by spraying, e.g. insecticides
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B64AIRCRAFT; AVIATION; COSMONAUTICS
    • B64UUNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
    • B64U10/00Type of UAV
    • B64U10/10Rotorcrafts
    • B64U10/13Flying platforms
    • B64U10/16Flying platforms with five or more distinct rotor axes, e.g. octocopters
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B64AIRCRAFT; AVIATION; COSMONAUTICS
    • B64UUNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
    • B64U60/00Undercarriages
    • B64U60/50Undercarriages with landing legs
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B64AIRCRAFT; AVIATION; COSMONAUTICS
    • B64UUNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
    • B64U2101/00UAVs specially adapted for particular uses or applications
    • B64U2101/45UAVs specially adapted for particular uses or applications for releasing liquids or powders in-flight, e.g. crop-dusting

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  • Engineering & Computer Science (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Pest Control & Pesticides (AREA)
  • Remote Sensing (AREA)
  • Vibration Dampers (AREA)

Abstract

A multi-rotor aircraft (10) includes a multi-rotor aircraft body M and a leg unit (36) mounted to the multi-rotor aircraft body M. The leg unit (36) has 4 legs (38). Each leg portion (38) includes a leg portion main body (46) and a reinforcing member (48). A gap C1 between the leg body (46) and the reinforcing member (48) is provided on one end side of the reinforcing member (48) in a direction orthogonal to the longitudinal direction of the leg body (46), and the reinforcing member (48) is connected to the leg body (46) on the other end side. When a load is applied from the other end side of the leg body (48) in a state where one end of the reinforcing member (48) is grounded, a gap C1 is provided between the two when the load is smaller than a predetermined load, and when the load is equal to or greater than the predetermined load, the gap C1 disappears and the two come into contact.

Description

Leg portion, leg portion unit and unmanned vehicles
Technical Field
The present invention relates to a leg portion, a leg portion unit, and an unmanned aerial vehicle, and more particularly to a leg portion and a leg portion unit for an unmanned aerial vehicle in which a scattering material is scattered, and an unmanned aerial vehicle having the same.
Background
As an example of such a conventional technique, patent document 1 discloses a landing apparatus for a rotary wing aircraft, which is characterized in that: the method comprises the following steps: a pair of cross tubes (cross tubes) attached to the bottom of the rotary wing aircraft at a predetermined interval and intersecting the body axis direction of the rotary wing aircraft; and a pair of leg pipes connected to both ends of each cross pipe in the axial direction of the machine body, wherein the leg pipes form a bent portion protruding upward, and a connection point with the cross pipe is formed at an appropriate position of the bent portion.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open No. 2005-343309
Disclosure of Invention
Problems to be solved by the invention
Patent document 1 discloses a simple improvement of the device, and attempts to absorb a large impact energy even when landing at a rapid sinking speed without causing damage to the vehicle body and passengers.
However, when an unmanned aircraft such as an unmanned helicopter or a multi-rotor aircraft lands, the load applied to the leg portion gradually increases from the time of contact with the landing surface to the time of complete landing. In the initial stage of landing with a small applied load, it is required to alleviate the impact due to contact with the landing surface and to improve the following ability to the undulation of the landing surface. However, patent document 1 does not disclose or suggest any means for simultaneously solving the above-described problems.
Therefore, the main objects of the present invention are: provided are a leg section, a leg section unit, and an unmanned aerial vehicle, which can alleviate impact caused by contact with a landing surface, improve the following performance with respect to undulation of the landing surface, and cope with a large load.
Means for solving the problems
According to an aspect of the present invention, there is provided a leg portion as follows: when a load is applied from the other end side with one end grounded, the ratio of the amount of displacement of the load application point of the 2 nd region where the load is equal to or greater than the predetermined load to the amount of change in the load is smaller than that of the 1 st region where the load is smaller than the predetermined load.
In the present invention, the ratio of the amount of displacement of the load application point in the 2 nd region where the load is equal to or greater than the predetermined load to the amount of change in the load (amount of displacement/amount of change in load) is smaller than in the 1 st region where the load is smaller than the predetermined load. In other words, the elastic constant of the leg portion of the 2 nd region where the load is large becomes larger than that of the 1 st region where the load is small. Therefore, for example, if 3 or more leg portions according to the present invention are used for an unmanned aerial vehicle, the leg portions are likely to deform because the proportion of the displacement amount of the load acting point to the amount of change in the load is large at the initial stage of landing when the load applied to the unmanned aerial vehicle is smaller than the predetermined load. As a result, the impact of the leg portion contacting the landing surface can be alleviated, and the unevenness of the landing surface can be absorbed, thereby improving the following performance with respect to the undulation of the landing surface. On the other hand, when landing is completed with an applied load equal to or greater than a predetermined load, the rate of the amount of displacement of the load application point with respect to the amount of change in the load is small, and therefore the leg portion is less likely to deform. As a result, energy can be absorbed to cope with a large load.
The "load application point" refers to a point to which a load is applied.
Further, the leg unit includes a leg unit main body and a reinforcing member provided so as to be connected to the leg unit main body and extend in a longitudinal direction of the leg unit main body, and the leg unit main body and the reinforcing member are configured so that, when a load is applied from the other end side of the leg unit main body in a state where one end of the leg unit main body or the reinforcing member is grounded, a gap is provided between the leg unit main body and the reinforcing member when the load is smaller than a predetermined load, and the gap disappears and the leg unit main body and the reinforcing member come into contact when the load is equal to or greater than the predetermined load.
In the present invention, when a load is applied to the leg portion main body in a state where one end portion of the leg portion main body or the reinforcing member is grounded, since a gap exists between the leg portion main body and the reinforcing member until a load equal to or larger than a predetermined amount is applied, a ratio of a displacement amount of a load acting point to a change amount of the load is large (an elastic constant of the leg portion is small). When a load of a predetermined level or more is applied to the leg body, the gap between the leg body and the reinforcing member disappears, and the leg body and the reinforcing member are integrated, so that the ratio of the displacement amount of the load acting point to the change amount of the load becomes small (the elastic constant of the leg portion becomes large). Therefore, for example, when 3 or more leg portions of the present invention are used for an unmanned aerial vehicle, the leg portions are likely to deform because a gap exists between the leg portion main body and the reinforcing member at the initial stage of landing when the load applied to the unmanned aerial vehicle is smaller than a predetermined load, and the ratio of the displacement amount of the load acting point to the amount of change in the load is large. As a result, the impact due to the leg portion contacting the landing surface can be alleviated, and the unevenness of the landing surface can be absorbed to improve the undulation of the landing surface. On the other hand, when landing is completed with an applied load equal to or greater than a predetermined load, the gap between the leg body and the reinforcing member disappears, and the leg body and the reinforcing member are integrated, and the ratio of the amount of displacement of the load application point to the amount of change in the load becomes small, so that the leg portion is less likely to deform. As a result, energy can be absorbed to cope with a large load.
Preferably, the gap is provided in a direction orthogonal to the longitudinal direction of the leg body on one end side of the reinforcing member, and the reinforcing member is connected to the leg body on the other end side. In this case, when the leg body or the one end portion of the reinforcing member is grounded and a load is applied to the leg body in a state where the gap is formed between the leg body and the reinforcing member on the one end portion side of the reinforcing member, the leg body is flexed so that the gap is narrowed. When the load is equal to or greater than the predetermined load, the gap between the leg body and the one end portion side of the reinforcing member is eliminated, and the leg body and the one end portion side of the reinforcing member are integrated. In this way, the following leg portions can be easily obtained: the ratio of the displacement amount of the load acting point in the 2 nd region where the load is equal to or greater than the predetermined load to the amount of change in the load is smaller than in the 1 st region where the load is smaller than the predetermined load.
Preferably, a concave portion is formed on one of the contact surfaces of the leg body and the reinforcing member, and a convex portion fitted into the concave portion is formed on the other contact surface. In this case, the leg body and the reinforcing member can be integrated more strongly.
More preferably, the reinforcing member is connected to the leg body at one end and is slidable relative to the leg body in the longitudinal direction at the other end, the leg body has a locking portion for locking the other end of the reinforcing member, and the gap is provided between the other end of the reinforcing member and the locking portion. In this case, when the leg body or the one end of the reinforcing member is grounded and a load is applied to the leg body in a state where a gap is formed between the other end of the reinforcing member and the locking portion of the leg body, the leg body is pressed downward. Accordingly, the other end of the reinforcing member slides in the longitudinal direction with respect to the leg body, and the gap is narrowed. When the load is equal to or greater than the predetermined load, the other end of the reinforcing member is locked to the locking portion of the leg body, and the leg body and the other end of the reinforcing member are integrated together without a gap therebetween. In this way, the following leg portions can be easily obtained: the ratio of the displacement of the load acting point to the amount of change in the load in the 2 nd region where the load is equal to or greater than the predetermined load is smaller than in the 1 st region where the load is smaller than the predetermined load.
Preferably, the reinforcing member is located above the leg body in a state where one end of the leg body or the reinforcing member is grounded. In this case, the reinforcing member can be easily replaced. For example, if 3 or more leg portions of the present invention are used for an unmanned aerial vehicle, the reinforcing member can be easily replaced when the unmanned aerial vehicle lands. Therefore, the reinforcing member having appropriate mechanical properties can be easily replaced in response to the impact at the time of landing, which differs depending on the weight and the descent speed of the unmanned aerial vehicle.
Preferably, the one end portion of the reinforcing member and the one end portion of the leg body are connected to each other so as to have a bulging shape and to form a through portion between the leg body and the reinforcing member. In this case, the reinforcing member or the vicinity of one end of the leg portion main body can be easily gripped and can function as a grip portion. Therefore, for example, when transporting an unmanned aerial vehicle having such a leg portion, the work can be smoothly performed by gripping the reinforcing member or the vicinity of one end portion of the leg portion main body.
More preferably, one end portion of the reinforcing member and one end portion of the leg main body are connected under a preload (initial load). In this case, the ratio of the displacement amount of the load acting point to the change amount of the load (the elastic constant of the leg portion) in the region where the load applied to the leg portion main body is smaller than the predetermined load can be adjusted in advance.
Preferably, a connecting portion between one end of the reinforcing member and one end of the leg main body is formed in a curved surface shape. In this case, for example, when the unmanned aerial vehicle having the leg portions is loaded and unloaded to and from a transportation rack, the unmanned aerial vehicle can easily slide on the rack, and the work can be smoothly performed.
Further, it is preferable that the leg main body is configured to have a bow shape so that, when a load is applied from the other end side in a state where the one end is grounded, a portion farther from the one end toward the other end side is grounded as the load becomes larger. In this case, when a load is applied to the leg body in a state where one end portion of the arcuate leg body is grounded, the grounded portion of the leg body moves (or expands) from the one end portion to a more distant portion from the other end portion as the load applied to the leg body increases. In the region where the load is small, the ratio of the displacement amount of the load application point to the amount of change in the load is large. On the other hand, in the region where the load is large, the ratio of the displacement amount of the load acting point to the change amount of the load becomes small. Therefore, for example, when 3 or more leg portions are used for the unmanned aerial vehicle, the leg portions are likely to be deformed because the vicinity of one end portion of the leg portion main body is grounded at the initial stage of landing when the load applied to the unmanned aerial vehicle is small, and the ratio of the displacement amount of the load application point to the change amount of the load is large. As a result, the impact due to the contact between the leg portions and the landing surface can be further alleviated, and the unevenness of the landing surface can be absorbed to improve the undulation of the landing surface. On the other hand, when landing with a large applied load is completed, the ground contact portion of the leg portion main body moves (or expands) toward the other end portion side, and the ratio of the displacement amount of the load acting point to the amount of change in the load becomes small, so that the leg portion is less likely to deform. As a result, it is possible to further absorb energy and cope with a large load. In this way, by using the arcuate leg portion main body, the operational effect in the case of using the leg portion main body and the reinforcing member becomes remarkable.
Further, there is provided a leg unit including the 3 or more legs and a case to which the legs are attached, wherein the legs are attached to the case such that one end of the leg is positioned below the case.
In the present invention, the tank has not only the original function of storing the dispersed matter and the fuel but also the function of supporting and connecting 3 or more leg portions.
Preferably, the case further includes a coupling member that is provided integrally with the case and couples the adjacent leg portions. In this case, the adjacent leg portions can be more strongly coupled by the coupling member integrally formed with the case.
Further, there is provided an unmanned aerial vehicle including the above-described 3 or more leg portions and an aircraft body to which the respective leg portions are attached, wherein the respective leg portions are attached to the aircraft body such that one end portions of the leg portions are positioned below the aircraft body.
When the unmanned aerial vehicle lands, it is required to mitigate the impact caused by the contact with the landing surface, improve the following ability to the undulation of the landing surface, and cope with a large load.
Preferably, the vehicle further includes a case to which the leg portions are attached, and the leg portions are attached to the case such that one end portions of the leg portions are positioned below the case. In this case, the leg portions can be connected to each other more firmly by a tank for storing the scatter and the fuel.
Further, a leg unit is provided, which includes: 3 or more leg portions arranged to be widened downward so as to be more largely opened when a load is applied from the other end side in a state where one end portion is grounded; a connecting member for connecting the leg portions to each other on the other end side; and a telescopic member which is capable of expanding and contracting and connects the leg opening portion of each leg portion with the leg opening portions of at least 1 other leg portion below the connecting member, wherein the connecting member and the telescopic member are configured to have a gap between them when a load is applied from the other end portion side of each leg portion in a state where one end portion of each leg portion is grounded, and to be in contact with each other when the load is smaller than a predetermined load and when the load is equal to or larger than the predetermined load.
In the present invention, when a load is applied to each leg portion from the other end side in a state where one end portion of each leg portion is grounded, the leg opening portion of each leg portion opens outward. Accordingly, the stretchable member provided below the coupling member is stretched outward, and the coupling member is relatively lowered toward the stretchable member, and finally comes into contact with the stretchable member. Since a gap is present between the coupling member and the extensible member until a load equal to or greater than a predetermined value is applied, the load is supported by the leg portion, and the ratio of the displacement amount of the load application point to the change amount of the load is large (the elastic constant of the leg portion is small). When a load equal to or greater than a predetermined value is applied, the coupling member and the extensible member come into contact with each other, and the load is supported not only by the leg portion but also by the extensible member, so that the ratio of the displacement amount of the load application point to the change amount of the load becomes small (the spring constant of the leg portion and the extensible member together becomes large). Therefore, for example, when the leg unit of the present invention is used for an unmanned aerial vehicle and the unmanned aerial vehicle is landed, a gap is present between the coupling member and the extensible member at the initial stage of landing when the applied load is smaller than the predetermined load, and the rate of the amount of displacement of the load acting point with respect to the amount of change in the load becomes large, so that the leg portion is easily deformed. As a result, the impact due to the contact between the leg portion and the landing surface can be alleviated, and the unevenness of the landing surface can be absorbed, thereby improving the following performance with respect to the undulation of the landing surface. On the other hand, when landing is completed with the applied load equal to or greater than the predetermined load, the connecting member contacts the telescopic members, and the ratio of the displacement amount of the load acting point to the change amount of the load becomes small, so that the leg portion is less likely to deform. As a result, energy can be absorbed to cope with a large load.
Effects of the invention
According to the present invention, a leg portion, a leg unit, and an unmanned aerial vehicle that can mitigate a collision due to contact with a landing surface, improve the following ability to undulate the landing surface, and cope with a large load can be obtained.
Drawings
Fig. 1 is a perspective view showing a multi-rotor aircraft according to an embodiment of the present invention.
Fig. 2 shows the multi-rotor aircraft of the embodiment of fig. 1, with (a) a front view and (b) a side view.
Fig. 3 is a perspective view showing an example of the leg unit.
Fig. 4 shows an example of a leg portion, in which (a) is a side view and (b) is a perspective view.
Fig. 5 is an end view showing the a-a end face of fig. 4 (a).
Fig. 6 is a graph showing a relationship between a load applied to the leg portion and a displacement amount of the load application point.
Fig. 7 is a diagram illustrating a transition of the grounding state of the leg portion with an increase in the load applied to the leg portion.
Fig. 8 is a schematic diagram showing another example of the leg unit.
Fig. 9 is a diagram showing an example of the distal end portion of the leg portion.
Fig. 10 shows other examples of leg portions, in which (a) is a side view and (b) is a perspective view.
Fig. 11 shows other examples of leg portions, in which (a) is a side view and (b) is a perspective view.
Fig. 12(a) is an end view showing the B-B end face of fig. 11(a), and (B) is an enlarged view showing a portion surrounded by a dashed-dotted line in fig. 11 (B).
Fig. 13 is a perspective view showing another example of the leg unit.
Fig. 14 shows the leg unit of fig. 13, wherein (a) is a diagram showing a state where a gap exists between the case and the extensible member, and (b) is a diagram showing a state where a gap does not exist between the case and the extensible member.
Detailed Description
Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, a case will be described in which the leg portions (foot portions) 38 according to an embodiment of the present invention are applied to the multi-rotor aircraft 10 as an example of an unmanned aircraft.
Referring to fig. 1 and 2, a multi-rotor aircraft 10 according to one embodiment of the present invention includes a main support 12. The main support portion 12 includes a disk-shaped rotor hub (hub portion/hub) 14 and a plurality of (6 in the present embodiment) cylindrical rotor rods (spokes/spokes) 16. The 6 rotor rods 16 are formed to extend radially and provided at substantially equal intervals (substantially 60 degrees intervals) in the circumferential direction on the side surface of the rotor head 14. A drive source 18, which is formed of, for example, a motor, and a single-rotor unit 20 are provided above the tip end portion of each rotor lever 16. The single-rotor unit 20 includes a rotor support portion 20a and a single rotor 20 b. The rotor support portion 20a extends vertically above the tip end portion of the rotor shaft 16 and is rotationally driven by the drive source 18. The single rotor 20b is supported at the upper end of the rotor support portion 20a and rotates together with the rotor support portion 20 a. The multi-rotor aircraft body M is configured in this manner.
Furthermore, multi-rotor aircraft 10 includes: a spreading device 22 for spreading the agent to the agricultural field; an antenna 24 for receiving and transmitting wireless signals; and a control device (not shown) for controlling the operation of multi-rotor aircraft 10. The chemical as used herein refers to a liquid or granular agricultural product such as herbicide, fertilizer, water, etc. The antenna 24 extends upward from the center of the main support 12, and the control device is housed in the main support 12. The spreading device 22 includes: a case 26 for containing a drug; a plurality of (2 in the present embodiment) arm-shaped pipes 28a, 28 b; a plurality of (2 in the present embodiment) nozzles 30a, 30b for discharging the medicine; and a pump 32 for pumping the medicine in the tank 26 to the nozzles 30a and 30b, and the dispenser 22 is provided below the main support 12. The tank 26 and the scattering device 22 are supported by a support portion 34 extending downward from the center of the rotor head 14. The pipes 28a and 28b are each formed in a substantially L shape, and extend radially from the side surface of the tank 26 in opposite directions to each other. The nozzles 30a and 30b are provided at the distal ends of the pipes 28a and 28b, respectively. The pump 32 is provided on the side of the tank 26. The medicine contained in the tank 26 is discharged downward from the nozzles 30a and 30b through the pipes 28a and 28 b.
Further, multi-rotor aircraft 10 contains leg units 36. Referring to fig. 3, the leg unit 36 includes: a plurality of (4 in the present embodiment) leg portions 38; a pair of connecting members 40 connecting the adjacent two leg portions 38; and a pair of coupling members 42 that couple the adjacent two leg portions 38. The leg unit 36 is coupled to the rotor head 14 via a plurality of (4 in the present embodiment) coupling members 44. Each of the connection members 44 connects the upper end portion of the corresponding leg portion 38 to the lower surface of the rotor head 14. Thus, each leg portion 38 is attached to the multi-rotor aircraft body M such that one end (lower end) of the leg portion 38 is positioned below the multi-rotor aircraft body M.
The leg portion 38 is explained with reference to fig. 4 and 5.
The leg portion 38 includes a leg portion main body 46 and a reinforcing member 48.
The leg unit main body 46 is made of, for example, ultra-high-molecular-weight polyethylene that is impact-resistant and is not easily broken, is formed in a substantially arcuate shape, and includes: a main body middle portion 50; a main body upper part 52 connected to an upper end of the main body middle part 50; and a lower body portion 54 connected to a lower end of the middle body portion 50. A groove-like recess 56 is formed in the center in the width direction of the surface of the body middle portion 50 and the body lower portion 54 facing the reinforcing member 48, from the upper end of the body middle portion 50 to the lower end of the body lower portion 54. Further, a through hole 58 for attaching the upper end portion of the reinforcing member 48 is formed in the upper end portion of the main body middle portion 50. A through hole 60 for attaching the lower end of the reinforcing member 48 is formed in the lower end of the main body lower portion 54.
The reinforcing member 48 is made of, for example, polyamide having excellent flexural strength, and includes an upper member portion 62 and a lower member portion 64, and the lower member portion 64 is connected to a lower end of the upper member portion 62. The component upper portion 62 is along the body middle portion 50 and is formed to be substantially the same length as the body middle portion 50. A through hole (not shown) for attachment to the body middle portion 50 is formed in an upper end portion of the member upper portion 62. The lower member 64 is bent from the lower end of the upper member 62 to be substantially V-shaped, and the front end of the lower member 64 is curved. A projection 66 is formed in the width direction center portion of the surface of the upper member portion 62 and the lower member portion 64 facing the leg portion main body 46, in a range from the upper end of the upper member portion 62 to the lower end of the lower member portion 64. The convex portion 66 has a size that can enter and exit the concave portion 56 (see fig. 5). In the projection 66, an edge portion of a portion formed in a central portion of the member lower portion 64 is formed in a wavy shape so as to be easily gripped. A through hole (not shown) for attaching the body lower portion 54 is formed in the lower end portion of the reinforcing member 48 (the convex portion 66).
In addition, the convex portion 66 of the reinforcing member 48 is fitted into the concave portion 56 of the leg main body 46, and in a state where the distal end portion of the member lower portion 64 is positioned so as to cover the distal end portion of the main body lower portion 54, a fastening member (not shown) such as a screw is inserted into and fixed to the through hole 58 of the leg main body 46 and the through hole at the upper end portion of the reinforcing member 48, and a fastening member (not shown) such as a screw is inserted into and fixed to the through hole 60 of the leg main body 46 and the through hole at the lower end portion of the reinforcing member 48. Thus, the reinforcing member 48 is provided to extend in the longitudinal direction of the leg main body 46, and the leg main body 46 and the reinforcing member 48 are connected on one end (lower end) side and the other end (upper end) side.
The upper end portions (the vicinity of the through hole 58) of the main body middle portions 50 of the adjacent leg portions 38 are connected to each other by rib-like connecting members 40 or 42. Further, the upper end portion of the body upper portion 52 of each leg portion 38 is coupled to the multi-rotor aircraft body M via the coupling member 44. The leg portion 38, the coupling members 40 and 42, and the coupling member 44 are coupled by a fastening member such as a screw.
In such a leg portion 38, the reinforcing member 48 is positioned above the leg portion main body 46 in a state where one end portion of the leg portion main body 46 or the reinforcing member 48 is grounded. One end portion of the reinforcing member 48 is connected to one end portion of the leg main body 46 as follows: the leg body 46 and the reinforcing member 48 are connected to each other by applying a preload (see fig. 4 a), and have a bulging outer shape, and a through portion 68 is formed between them. A connection portion between one end of the reinforcing member 48 and one end of the leg main body 46 is formed in a curved surface shape. Further, on each contact surface where the leg main body 46 and the reinforcing member 48 are brought into contact by applying a load of a predetermined value or more to the leg 38, a concave portion 56 is formed on the surface on the leg main body 46 side, and a convex portion 66 that fits into the concave portion 56 is formed on the surface on the reinforcing member 48 side. In the lower body 54 shown in fig. 4(a), the shape of the through-hole 60 of the leg body 46 and the shape of the through-hole at the lower end of the reinforcing member 48 before assembly are shown by a chain line, and the shape when assembled is shown by a solid line.
As a result of the static load test of the multi-rotor aircraft 10, the relationship between the load applied to the leg portion 38 and the displacement amount of the load application point X shown in fig. 6 can be obtained. In this test, a load is applied to the multi-rotor aircraft 10 from above with one end of the reinforcing member 48 of each leg portion 38 grounded, and the amount of displacement of the load application point X in the vertical direction is measured. In the present embodiment, the load application point X is a connection portion between the body upper portion 52 on the other end side of the leg body 46 and the connection member 44 (see fig. 4 (a)). The load on the horizontal axis in fig. 6 is the total load applied to the 4 leg portions 38. Thus, the load applied to the load application point X of each leg portion 38 can be regarded as one fourth of the "total load applied to the 4 leg portions 38".
Referring to fig. 6 and 7, at a point P1 where the load is zero, as shown in fig. 7(a), the lower end portion of the reinforcing member 48 is grounded, and a gap C1 exists between the leg main body 46 and the reinforcing member 48. Referring to fig. 5, the gap C1 is provided between the concave portion 56 and the convex portion 66 in the direction orthogonal to the longitudinal direction of the leg main body 46 on the one end portion side of the reinforcing member 48. In the present embodiment, even if the load is zero, the convex portion 66 is slightly inserted into the concave portion 56. This prevents the convex portion 66 from being fitted into and removed from the concave portion 56 when a load is applied. At a point P2 where the load is 17kgf, as shown in fig. 7(b), the lower end of the reinforcing member 48 is grounded to the body lower portion 54 of the leg main body 46, and the gap C1 between the leg main body 46 and the reinforcing member 48 disappears. In this test, 17/4kgf corresponds to a predetermined load applied to each load application point X. At a point P3 where the load is approximately 46kgf (the upper limit of the normal use range), as shown in fig. 7(C), the reinforcing member 48 is not grounded and the lower end portion of the body middle portion 50 of the leg portion body 46 is grounded in a state where there is no gap C1. At a point P4 where the load is substantially 57kgf (reinforcing member breakage range), as shown in fig. 7(d), the main body middle portion 50 of the leg portion main body 46 is grounded over a large area in a state where the gap C1 is not provided. At the point P4, the coupling members 40, 42 are also greatly deformed.
As described above, when a load is applied from the other end side, the leg main body 46 is grounded at a position farther from the one end toward the other end side as the load increases. When a load is applied from the other end side of the leg body 46 in a state where one end of the reinforcing member 48 is grounded, and when the load applied to the load application point X in each leg 38 is smaller than a predetermined load, the gap C1 exists between the leg body 46 and the reinforcing member 48, but when the load is equal to or greater than the predetermined load, the gap C1 disappears, and the two are brought into contact with each other and integrated. Therefore, when a load is applied from the other end side with one end of the leg portion 38 grounded, the ratio of the amount of displacement of the load acting point X in the 2 nd region R2 where the load is equal to or greater than the predetermined load to the amount of change in the load applied to the leg portion 38 (amount of displacement/amount of change in load: the slope of the characteristic curve shown in fig. 6) becomes smaller than in the 1 st region R1 where the load applied to each leg portion 38 is smaller than the predetermined load. In other words, the elastic constant of the leg portion 38 of the 2 nd region R2, in which the load is large, becomes larger than that of the 1 st region R1, in which the load is small.
According to the multi-rotor aircraft 10, when a load is applied to the leg body 46 in a state in which the one end portion of the reinforcing member 48 is grounded in each leg portion 38, since the gap C1 exists between the leg body 46 and the reinforcing member 48 until a load equal to or greater than a predetermined amount is applied, the ratio of the displacement amount of the load application point X to the change amount of the load becomes large (the spring constant of the leg portion 38 becomes small). When a load equal to or greater than a predetermined value is applied to the leg body 46, the gap C1 between the leg body 46 and the reinforcing member 48 disappears, and the leg body 46 and the reinforcing member 48 are integrated, so that the ratio of the displacement amount of the load application point X to the change amount of the load becomes small (the spring constant of the leg 38 becomes large). Therefore, when the multi-rotor aircraft 10 is landed, at the initial stage of landing where the load applied to each leg portion 38 is smaller than the predetermined load, the clearance C1 exists between the leg portion main body 46 and the reinforcing member 48, and the rate of the displacement amount of the load application point X with respect to the change amount of the load becomes large, so that the leg portion 38 is easily deformed. As a result, the impact due to the contact between the leg portions 38 and the landing surface can be alleviated, and the irregularities of the landing surface can be absorbed, thereby improving the following performance with respect to the undulation of the landing surface. On the other hand, when landing is completed with a load equal to or greater than a predetermined load applied to each leg portion 38, the gap C1 between the leg portion main body 46 and the reinforcing member 48 disappears, the leg portion main body 46 and the reinforcing member 48 are integrated, and the proportion of the amount of displacement of the load application point X with respect to the amount of change in the load becomes small, so that the leg portion 38 is less likely to deform. As a result, energy can be absorbed to cope with a large load.
Further, when a load is applied to the leg main body 46 in a state where one end portion of the arcuate leg main body 46 is grounded, the grounded portion of the leg main body 46 moves (or expands) from the one end portion toward a portion farther toward the other end portion side as the load applied to the leg main body 46 becomes larger. In the region where the load is small, the ratio of the displacement amount of the load application point X to the change amount of the load is large. On the other hand, in a region where the load is large, the ratio of the displacement amount of the load application point X to the amount of change in the load is small. Therefore, when the multi-rotor aircraft 10 having the leg portions 38 is landed, the vicinity of one end portion of the leg portion main body 46 is grounded at the initial stage of landing where the applied load is small, and the proportion of the displacement amount of the load application point X with respect to the change amount of the load is large, so that the leg portions 38 are easily deformed. As a result, the impact due to the contact between the leg portions 38 and the landing surface can be further alleviated, and the irregularities of the landing surface can be absorbed, thereby improving the following ability to the undulations of the landing surface. On the other hand, when landing with a large applied load is completed, the ground contact portion of the leg main body 46 moves (or expands) toward the other end portion side, and the ratio of the displacement amount of the load application point X to the amount of change in the load becomes small, so that the leg 38 is difficult to deform. As a result, it is possible to further absorb energy and cope with a large load. In this manner, the use of the arcuate leg main body 46 provides a significant effect.
In a state where one end of the leg main body 46 or the reinforcing member 48 is grounded, the reinforcing member 48 is positioned above the leg main body 46, and therefore, the reinforcing member 48 can be easily replaced. Therefore, the reinforcing member 48 can be easily replaced when the multi-rotor aircraft 10 lands, and the multi-rotor aircraft 10 can be easily replaced with a reinforcing member having suitable mechanical properties in response to impacts during landing that vary depending on the weight and descent speed of the multi-rotor aircraft.
Since the one end portion of the reinforcing member 48 and the one end portion of the leg body 46 are connected to each other so as to have a bulging outer shape and the penetrating portion 68 is formed between the leg body 46 and the reinforcing member 48, the reinforcing member 48 or the vicinity of the one end portion of the leg body 46 can be easily gripped to function as a gripping portion. Therefore, when transporting the multi-rotor aircraft 10, the work can be smoothly performed by gripping the reinforcing member 48 or the vicinity of one end of the leg main body 46.
Since the one end portion of the reinforcing member 48 and the one end portion of the leg main body 46 are connected under the condition that the preload (initial load) is applied, the ratio of the displacement amount of the load application point X to the change amount of the load (elastic constant of the leg portion 38) in the region where the load applied to the leg main body 46 is smaller than the predetermined load can be adjusted in advance.
Since the connection portion between the one end portion of the reinforcing member 48 and the one end portion of the leg main body 46 is formed in a curved surface shape, the multi-rotor aircraft 10 can easily slide on a rack when the multi-rotor aircraft 10 is attached to and detached from the rack for transportation, and thus the operation can be smoothly performed.
Since it is required to reduce the impact due to the contact with the landing surface and improve the following ability to the undulation of the landing surface and to cope with a large load when the multi-rotor aircraft 10 lands, the leg portion 38 can be applied to the multi-rotor aircraft 10.
The above-described operational effects can be similarly achieved also in the leg portion 38a shown in fig. 10 described later.
In the leg portion 38, in a state where the gap C1 is formed between the leg portion main body 46 and the reinforcing member 48 on the one end portion side of the reinforcing member 48, when the leg portion main body 46 or the one end portion of the reinforcing member 48 is grounded and a load is applied to the leg portion main body 46, the leg portion main body 46 is flexed so as to narrow the gap C1. When the load applied to the leg portion 38 is equal to or greater than a predetermined load, the gap C1 between the leg portion main body 46 and the one end portion side of the reinforcing member 48 disappears, and the two are integrated. In this manner, the leg portion 38 can be easily obtained as follows: the ratio of the displacement amount of the load acting point X in the 2 nd region R2 having a load equal to or greater than the predetermined load to the amount of change in the load is smaller than in the 1 st region R1 having a load smaller than the predetermined load.
In the leg portion 38, the recessed portion 56 is formed on the surface on the leg portion main body 46 side, and the protruding portion 66 that fits into the recessed portion 56 is formed on the surface on the reinforcing member 48 side, so that the leg portion main body 46 and the reinforcing member 48 can be integrated more strongly.
In the above embodiment, the leg unit 36 is not connected to the tank 26, but is not limited thereto. A leg unit 36a as shown in fig. 8 may also be used. The leg unit 36a corresponds to a structure in which the leg unit 36 shown in fig. 3 is connected to the tank 26 a. In the leg unit 36a, the main body upper portions 52 of the respective legs 38 are connected by the case 26a so that one end portions (lower end portions) of the legs 38 are positioned below the case 26 a. The main body upper portion 52 and the case 26a are connected by a fastening member (not shown) such as a screw. The tank 26a and the coupling members 40 and 42 are integrally provided by fastening members such as screws, for example. Leg unit 36a is coupled to multi-rotor aircraft body M via connection member 44 connected to body upper portion 52 of each leg 38.
According to the leg unit 36a, the tank 26a not only has an original function of storing the dispersed matter and the fuel but also has a function of supporting and connecting 4 legs 38, and the legs 38 can be strongly connected. The adjacent leg portions 38 can be further strongly coupled by coupling members 40, 42 integrated with the case 26 a. As described above, each leg portion 38 is supported not only by the case 26a but also by the coupling members 40 and 42, and the support of the leg portion 38 can be shared, and the leg portion 38 can be supported more strongly.
In the above embodiment, the leg portion 38 is configured such that the tip of the convex portion 66 of the reinforcing member 48 enters the concave portion 56 of the leg portion main body 46 on the one end portion side of the reinforcing member 48 (the lower end portion side of the member upper portion 62) even in a state where the load is zero, but the present invention is not limited thereto. As shown in fig. 9, the leg portion 38 may be configured such that, in a state where the load is zero, the tip of the convex portion 66 of the reinforcing member 48 does not enter the concave portion 56 of the leg portion main body 46 at the one end portion side of the reinforcing member 48. Further, the leg body may be provided with a convex portion and the reinforcing member may be provided with a concave portion. Further, the leg portion may be configured by using a leg portion main body and a reinforcing member without a concave portion and a convex portion.
The reinforcing member 48 may not include the member lower portion 64. Thus, the lower end portion of the leg portion main body 46 and the lower end portion of the reinforcing member may not necessarily be connected.
Next, a leg portion 38a according to another embodiment of the present invention will be described with reference to fig. 10.
The leg portion 38a includes a leg portion main body 70 and a reinforcing member 72.
The leg portion main body 70 is formed of, for example, ultra-high molecular weight polyethylene that is impact resistant and is hard to break, and is formed in a substantially arcuate shape, and the leg portion main body 70 includes: a body mid-section 74; a body upper portion 76 connected to an upper end portion of the body middle portion 74; and a lower body portion 78 connected to a lower end of the middle body portion 74. A groove-like recess 80 is formed in the center in the width direction of the surface of the body middle portion 74 and the body lower portion 78 that faces the reinforcing member 72, from the upper end of the body middle portion 74 to the lower end of the body lower portion 78. Further, a locking portion 82 that locks the other end portion (upper end portion) of the reinforcing member 72 is formed at the lower end of the main body upper portion 76. The lower end of the main body lower portion 78 is formed in a curved surface shape, and a through hole 84 for attaching the lower end of the reinforcing member 72 is formed in the lower end of the main body lower portion 78.
The reinforcing member 72 is made of, for example, polyamide having excellent flexural strength, and includes: a component upper portion 86; and a lower component part 88 connected to a lower end of the upper component part 86. The member upper portion 86 is formed along the body middle portion 74 to have substantially the same length as the body middle portion 74, and has a protrusion portion 90 formed at an upper end portion thereof. The lower member 88 is bent from the lower end of the upper member 86 to be formed in a substantially V-shape. In the widthwise central portion of the surface of the upper member portion 86 and the lower member portion 88 which faces the leg portion body 70, a projection 92 is formed so as to extend from the upper end of the upper member portion 86 to the lower end of the lower member portion 88 and further to extend from the lower member portion 88 and to be bent toward the upper member portion 86. The convex portion 92 has a size that can fit into the concave portion 80, and by fitting the convex portion 92 into the concave portion 80, it is possible to prevent a positional shift in the width direction of the reinforcing member 72 with respect to the leg portion body 70, and it is possible to position the reinforcing member 72 on the leg portion body 70. A through hole (not shown) for attaching the body lower portion 78 is formed in the lower end portion of the reinforcing member 72 (the convex portion 92).
In a state where the convex portion 92 of the reinforcing member 72 is positioned so as to fit into the concave portion 80 of the leg body 70, a fastening member (not shown) such as a screw is inserted into and fixed to the through hole 84 of the leg body 70 and the through hole at the lower end portion of the reinforcing member 72. Thus, the reinforcing member 72 is provided to extend in the longitudinal direction of the leg body 70, and the leg body 70 and the reinforcing member 72 are connected on the one end (lower end) side. Further, a gap C2 is provided between the protrusion 90 of the other end portion of the reinforcing member 72 and the locking portion 82 of the leg body 70, and the reinforcing member 72 is provided so as to be slidable relative to the leg body 70 in the longitudinal direction on the other end portion (upper end portion) side.
The lower ends of the body upper portions 76 of the adjacent leg portions 38a (slightly above the locking portions 82) are connected to each other by rib-like connecting members 40 or 42. Further, the upper end portion of the body upper portion 76 of each leg portion 38a is coupled to the multi-rotor aircraft body M via the coupling member 44. The leg portion 38a, the coupling members 40 and 42, and the coupling member 44 are coupled by a fastening member such as a screw.
In the leg portion 38a, the reinforcing member 72 is positioned above the leg portion main body 70 in a state where one end portion of the leg portion main body 70 is grounded. One end of the reinforcing member 72 is connected to one end of the leg body 70 under a preload (see fig. 10 a), and the reinforcing member 72 and the leg body 70 are connected to each other so as to have a bulging outer shape and to form a through-hole 94 between the reinforcing member 72 and the leg body 70. A connection portion between one end of the reinforcing member 72 and one end of the leg body 70 is formed in a curved surface shape. In each contact surface where the leg body 70 and the reinforcing member 72 contact each other by applying a load of a predetermined value or more to the leg 38a, a concave portion 80 is formed on the surface on the leg body 70 side, and a convex portion 92 that fits into the concave portion 80 is formed on the surface on the reinforcing member 72 side. In the lower body portion 78 shown in fig. 10(a), the shape before assembly of the through hole 84 of the leg body 70 and the through hole at the lower end portion of the reinforcing member 72 is shown by a chain line, and the shape during assembly is shown by a solid line.
Further, when a load is applied from the other end side in a state where the one end is grounded, the leg portion main body 70 is grounded at a position farther from the one end toward the other end side as the load becomes larger. When a load is applied from the other end side of the leg body 70 in a state where one end of the leg body 70 is grounded, and when the load applied to the load application point (the connection portion between the leg 38a and the connection member 44) by each leg 38a is smaller than a predetermined load, a gap C2 (see fig. 10) exists between each leg body 70 and the reinforcing member 72, but when the load is equal to or greater than the predetermined load, the gap C2 disappears, and the two are brought into contact with each other and integrated. Therefore, when a load is applied from the other end side in a state where one end of the leg portion 38a is grounded, the ratio of the amount of displacement of the load acting point in the 2 nd region (corresponding to the 2 nd region R2 in fig. 6) where the load applied to each leg portion 38a is equal to or greater than the predetermined load to the amount of change in the load applied to the leg portion 38a becomes smaller than in the 1 st region (corresponding to the 1 st region R1 in fig. 6) where the load applied to each leg portion 38a is smaller than the predetermined load.
According to the multi-rotor aircraft including the leg portion 38a, in a state where the gap C2 is formed between the other end portion of the reinforcing member 72 and the locking portion 82 of the leg portion body 70, when the one end portion of the leg portion body 70 is grounded and a load is applied to the leg portion body 70, the leg portion body 70 is pressed downward. Accordingly, the other end of the reinforcing member 72 slides in the longitudinal direction (Y1 direction) with respect to the leg body 70, and the gap C2 becomes narrower. When the load applied to each leg portion 38a is equal to or greater than the predetermined load, the other end portion (protrusion 90) of the reinforcing member 72 is locked to the locking portion 82 of the leg body 70, and the gap C2 between the leg body 70 and the other end portion of the reinforcing member 72 disappears and the two are integrated. In this way, the leg portion 38a can be easily obtained as follows: the ratio of the displacement of the load acting point to the amount of change in the load in the 2 nd region where the load is equal to or greater than the predetermined load is smaller than in the 1 st region where the load is smaller than the predetermined load.
Further, with reference to fig. 11 and 12, the leg portion 38b according to another embodiment of the present invention will be described.
The leg portion 38b includes a leg portion main body 96 and a reinforcing member 98.
The leg unit body 96 is made of, for example, ultra-high molecular weight polyethylene that is impact resistant and is not easily broken, and is formed in a substantially arcuate shape, and the leg unit body 96 includes: a main body middle portion 100; a main body upper part 102 connected to an upper end of the main body middle part 100; and a lower body part 104 connected to a lower end of the middle body part 100. A pair of locking portions 106a, 106b are formed at a position slightly below the upper end of the body middle portion 100 so as to sandwich the surface of the body middle portion 100 facing the reinforcing member 98. At the lower end of the face of the body middle portion 100 opposed to the reinforcing member 98, a protrusion portion 110 is provided, the protrusion portion 110 having a slit 108 extending in the longitudinal direction of the leg portion 38 b. A groove-like recess 112 is formed in the width direction center portion of the opposing surface in a range from the upper end of the main body middle portion 100 to the protrusion 110. Further, a pair of groove- like recesses 114a, 114b extending in the longitudinal direction of the leg portion 38b are formed on both side surfaces of the upper end portion of the main body center portion 100. The lower end of the main body lower portion 104 is formed in a curved surface shape.
The reinforcing member 98 is made of, for example, polyamide having excellent flexural strength, is formed in a substantially V-shape, and is provided so as to face the main body middle portion 100 of the leg portion main body 96. The reinforcing member 98 includes a member body 116. A locking portion 118 is provided at an upper end of the member body 116. The locking portion 118 includes a pair of convex portions 120a and 120b that are slidable in the concave portions 114a and 114b (see fig. 12 (a)). A plate-like portion 122 into which the slit 108 of the protrusion 110 is inserted is provided at the lower end of the member main body 116. A projection 124 is formed in the width direction center portion of the surface of the member body 116 and the locking portion 118 facing the leg portion body 96, from the upper end of the locking portion 118 to the lower end of the member body 116. The convex portion 124 has a size that can fit into the concave portion 112, and the convex portion 124 is fitted into the concave portion 112, whereby positional displacement in the width direction of the reinforcing member 98 with respect to the leg portion body 96 can be prevented.
The convex portions 124, 120a, and 120b of the reinforcing member 98 are fitted into the concave portions 112, 114a, and 114b of the leg body 96, respectively, and the projection 110 and the plate portion 122 are fixed to each other by a fastening member (not shown) such as a screw in a state where the plate portion 122 of the reinforcing member 98 is inserted into the slit 108 of the leg body 96. Thus, the reinforcing member 98 is provided to extend in the longitudinal direction of the leg body 96, and the leg body 96 and the reinforcing member 98 are connected on the one end (lower end) side. Further, a clearance C3 (see fig. 11 a) is provided between the locking portion 118 of the reinforcing member 98 and the locking portions 106a and 106b of the leg body 96, and the reinforcing member 98 is provided so as to be slidable relative to the leg body 96 in the longitudinal direction on the other end portion (upper end portion) side. In the leg portion 38b, the reinforcing member 98 is positioned below the leg portion body 96 in a state where one end portion of the leg portion body 96 is grounded.
According to the multi-rotor aircraft using the leg portion 38b, in a state where the gap C3 is formed between the locking portion 118 of the reinforcing member 98 and the locking portions 106a and 106b of the leg body 96, when one end portion of the leg body 96 is grounded and a load is applied from the other end portion side of the leg body 96, the leg body 96 is pressed downward and bent. Accordingly, the locking portion 118 of the reinforcing member 98 slides in the longitudinal direction (Y2 direction) along the recessed portions 114a and 114b with respect to the leg main body 96, and the gap C3 gradually narrows. When the load applied to each leg portion 38b is equal to or greater than the predetermined load, the locking portion 118 of the reinforcing member 98 is locked to the locking portions 106a and 106b of the leg portion body 96, and the gap C3 disappears, so that the leg portion body 96 and the reinforcing member 98 are integrated. In this way, the leg portion 38b can be easily obtained as follows: the ratio of the displacement of the load acting point to the amount of change in the load in the 2 nd region (with respect to the 2 nd region R2 in fig. 6) where the load is equal to or greater than the predetermined load is smaller than in the 1 st region (the 1 st region R1 in fig. 6) where the load is smaller than the predetermined load.
Further, a leg unit 36b according to another embodiment of the present invention will be described with reference to fig. 13 and 14.
The leg unit 36b includes: a plurality of (4 in the present embodiment) leg portions 38 d; a case 26b functioning as a connecting member for connecting the leg portions 38 d; and 2 telescoping members 126 joining the opposing 2 leg portions 38 d.
Each leg portion 38d is formed in a substantially arcuate shape including: a mounting portion 128 mounted to the case 26 b; a leg expanding portion 130 connected to a lower end of the mounting portion 128 and capable of expanding (expanding/spreading); and a support portion 132 provided to the leg expanding portion 130 to support the telescopic member 126. The lower end of the leg opening portion 130 is formed in a curved surface shape.
The 4 leg portions 38d are arranged to be widened downward so as to be further opened when a load is applied from the other end portion (upper end portion) side in a state where one end portion (lower end portion) is grounded. The case 26b connects the respective leg portions 38d to each other on the other end side. The telescopic member 126 is made of, for example, rubber, and connects the leg expanding portions 130 (support portions 132) of the opposing leg portions 38d to each other below the case 26 b.
The leg unit 36b is connected to the multi-rotor aircraft body M via a connection member (not shown) connected to the other end of the leg 38d so that one end of the leg 38d is positioned below the multi-rotor aircraft body M (see fig. 1).
According to the multi-rotor aircraft including the leg unit 36b, when a load is applied to each leg portion 38d from the other end side while one end portion of each leg portion 38d is grounded, the leg opening portion 130 of each leg portion 38d opens outward. Accordingly, the extensible member 126 provided below the tank 26b functioning as the connecting member is pulled outward, and the tank 26b is relatively lowered toward the extensible member 126, and finally comes into contact with the extensible member 126. Since the clearance C4 exists between the case 26b and the extensible member 126 until a load equal to or greater than a predetermined value is applied, the load is supported by the leg portion 38d, and the ratio of the displacement amount of the load application point to the change amount of the load is large (the spring constant of the leg portion 38d is small). When a load equal to or greater than a predetermined value is applied, the case 26b contacts the extensible member 126, and the load is supported not only by the leg portion 38d but also by the extensible member 126, so that the ratio of the displacement amount of the load application point to the change amount of the load becomes small (the spring constant of the leg portion 38d and the extensible member 126 together becomes large). Therefore, when the multi-rotor aircraft having the leg unit 36b is landed, the gap C4 is present between the tank 26b and the telescopic member 126 at the initial stage of landing when the applied load is smaller than the predetermined load, and the displacement amount of the load application point is large in proportion to the amount of change in the load, so that the leg portion 38d is easily deformed. As a result, the impact due to the contact between the leg portion 38d and the landing surface can be alleviated, and the unevenness of the landing surface can be absorbed, thereby improving the following performance with respect to the undulation of the landing surface. On the other hand, when landing is completed with the applied load equal to or greater than the predetermined load, the case 26b contacts the extensible member 126, and the rate of the amount of displacement of the load application point with respect to the amount of change in the load becomes small, so that the leg portion 38d is less likely to deform. As a result, energy can be absorbed to cope with a large load.
In the embodiment shown in fig. 4, the reinforcing member 48 is grounded when the load is zero, but the present invention is not limited thereto. The leg main body may be grounded when the load is zero.
In the embodiment shown in fig. 10, the leg portion main body 70 is mainly grounded when the load is zero, but is not limited thereto. The reinforcing member may be mainly grounded when the load is zero.
In the embodiment shown in fig. 4 and 8, the reinforcing member has a bulged shape, but is not limited thereto. The leg main body may have a bulging shape.
In the leg unit 36a shown in fig. 8, the case 26a is provided integrally with the coupling members 40, 42, but is not limited thereto. The tank 26a and the coupling members 40 and 42 may be separate.
In the embodiment shown in fig. 13, the telescopic member 126 connects the 2 leg portions 38d opposed to each other, but is not limited thereto. The telescopic member may be configured to connect the leg opening portion of each leg portion to at least the leg opening portions of the other at least 1 leg portion.
In the above-described embodiment, the case where the multi-rotor aircraft has 4 leg portions has been described, but the present invention is not limited thereto. The multi-rotor aircraft can be provided with more than 3 leg parts.
In the above-described embodiments, the present invention is applied to a multi-rotor aircraft, but is not limited thereto. The invention can be applied to any unmanned aerial vehicle such as single-rotor helicopters and hot air balloons.
While the preferred embodiments of the present invention have been described above, it is apparent that various modifications can be made without departing from the scope and spirit of the present invention. The scope of the invention is only limited by the appended claims.
Description of the symbols
10 multi-rotor craft (multicopter)
26. 26a, 26b box
36. 36a, 36b leg unit
38. 38a, 38b, 38c, 38d
40. 42 connecting member
44 connecting part
46. 70, 96 leg body
48. 72, 98 reinforcing member
56. 80, 112, 114a, 114b recess
66. 92, 120a, 120b, 124 convex part
68. 94 penetration part
82. 106a, 106b, 118 latch
126 telescopic parts
130 leg flare
Gaps of C1, C2, C3 and C4
M multi-rotor aircraft body
Region 1 of R1
Region 2 of R2
Point of application of the X load.

Claims (15)

1. A leg support part is characterized in that,
when a load is applied from the other end side with one end grounded, the ratio of the amount of displacement of the load acting point of the 2 nd region where the load is equal to or greater than a predetermined load to the amount of change in the load is smaller than that of the 1 st region where the load is smaller than the predetermined load.
2. A leg portion, comprising:
a leg body; and
a reinforcing member connected to the leg portion main body and extending in a longitudinal direction of the leg portion main body,
the leg body and the reinforcing member are configured such that, when a load is applied from the other end side of the leg body in a state where one end of the leg body or the reinforcing member is grounded, a gap is present between the leg body and the reinforcing member when the load is smaller than a predetermined load, and the gap disappears and the leg body and the reinforcing member come into contact with each other when the load is equal to or greater than the predetermined load.
3. The leg portion of claim 2,
the gap is provided along a direction orthogonal to the longitudinal direction of the leg body on the one end side of the reinforcing member,
the reinforcing member is connected to the leg body on the other end side.
4. The leg portion of claim 3,
a concave portion is formed in one of the contact surfaces where the leg body and the reinforcing member contact each other when the predetermined load or more is applied, and a convex portion that fits into the concave portion is formed in the other contact surface.
5. The leg portion of claim 2,
the reinforcing member is provided so as to be connected to the leg main body on one end side and so as to be relatively slidable in a longitudinal direction with respect to the leg main body on the other end side,
the leg body has a locking part for locking the other end of the reinforcing member,
the gap is provided between the other end of the reinforcing member and the locking portion.
6. The leg unit according to any one of claims 2 to 5,
the reinforcing member is positioned above the leg body in a state where one end of the leg body or the reinforcing member is grounded.
7. The leg section according to any one of claims 2 to 6,
one end of the reinforcing member and one end of the leg body are connected to each other so as to have a bulging outer shape and to form a through-hole between the leg body and the reinforcing member.
8. The leg portion of claim 7,
one end portion of the reinforcing member and one end portion of the leg main body are connected under a preload.
9. The leg part of claim 7 or 8,
a connecting portion between one end of the reinforcing member and one end of the leg main body is formed in a curved surface shape.
10. The leg section according to any one of claims 2 to 9,
the leg body is configured to be arcuate such that, when a load is applied from the other end side while one end is grounded, a portion farther from the one end toward the other end side is grounded as the load increases.
11. A leg unit, comprising:
3 or more leg portions as claimed in any one of claims 1 to 10; and
a case in which the leg portions are installed,
each of the leg portions is attached to the box such that one end portion of the leg portion is positioned below the box.
12. The leg unit of claim 11,
and a connecting member provided integrally with the case and connecting the adjacent leg portions.
13. An unmanned aerial vehicle, comprising:
3 or more leg portions as claimed in any one of claims 1 to 10; and
an aircraft body provided with the leg parts,
each of the leg portions is attached to the aircraft body such that one end portion of the leg portion is located below the aircraft body.
14. The unmanned aerial vehicle of claim 13,
and a case in which the leg portions are mounted,
each of the leg portions is attached to the box such that one end portion of the leg portion is positioned below the box.
15. A leg unit, comprising:
3 or more leg portions arranged to be widened downward so as to be able to be further opened when a load is applied from the other end side in a state where one end portion is grounded;
a connecting member that connects the leg portions to each other on the other end side; and
a telescopic member which is telescopic and connects the leg opening portion of each leg portion to the leg opening portions of at least 1 other leg portion below the connecting member,
the connecting member and the extensible member are configured to include a gap between the two members when a load is applied from the other end side of each of the leg portions in a state where one end portion of each of the leg portions is grounded, and to be in contact with each other when the load is smaller than a predetermined load or larger.
CN201880049416.9A 2017-07-26 2018-04-27 Leg portion, leg portion unit and unmanned vehicles Active CN110958975B (en)

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JP2017144683A JP6448719B1 (en) 2017-07-26 2017-07-26 Legs, leg units and unmanned air vehicles
PCT/JP2018/017340 WO2019021564A1 (en) 2017-07-26 2018-04-27 Legs, leg unit, and unmanned flying body

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WO2019021564A1 (en) 2019-01-31
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KR20200019977A (en) 2020-02-25
JP2019025968A (en) 2019-02-21

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