drone

Abstract

To provide a high practical drone.SOLUTION: A drone equipped with an airbag 22 deploying downward when falling, is provided with a vent hole 32 accepting an outflow of inside gas at grounding. The vent hole accepts the outflow of inside gas at grounding, so that the bounding of the drone due to a pressure rise in the airbag is prevented.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a drone capable of deploying an airbag. [Background technology]

[0002] The following patent document describes a drone that can deploy airbags to cushion the impact when it falls and hits the ground. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-34761 Summary of the Invention [Problem to be solved by the invention]

[0004] Although the drones described in the above patent documents absorb the impact of landing, they may bounce after landing due to the increased pressure inside the airbag, causing them to re-collide with the ground with the part of the drone without the airbag facing downwards. Preventing such re-collisions would improve the practicality of drones. The present invention was made in light of this situation, and aims to provide a highly practical drone. [Means for solving the problem]

[0005] In order to solve the above problems, the drone of the present invention is A drone equipped with an airbag that deploys downward when falling, and the airbag is provided with a vent hole that allows the internal gas to escape when landing, A vent hole opening mechanism is provided inside the airbag, has a strap with both ends connected to opposing upper and lower parts of the airbag, and closes the vent hole in a tensioned state due to the gas pressure inside the airbag, and when the airbag deforms upon landing, the strap loosens, opening the vent hole. and, an inflator that deploys the airbag by adiabatically expanding compressed gas into the airbag, The inflator is configured to heat the gas released into the airbag so that the temperature of the gas in the airbag immediately after deployment is lower than the ambient temperature. It is characterized by: [Effects of the Invention]

[0006] In the drone of the present invention, the vent holes allow the gas inside to escape when the drone lands, preventing the drone from bouncing due to an increase in pressure inside the airbag.

[0007] The drone of the present invention may be configured to have a vent hole opening mechanism that opens the vent hole when the airbag deforms upon landing. Specifically, for example, the vent hole opening mechanism may be configured by providing a strap inside the airbag, with both ends connected to opposing upper and lower parts of the airbag and tensioned by the gas pressure inside the airbag to close the vent hole, and by the airbag deforming upon landing, the strap slackens, opening the vent hole.

[0008] The drone of the present invention may also be provided with an outflow resistance mechanism that provides resistance to the outflow of gas from the vent hole. In this case, for example, a sub-chamber may be provided whose interior communicates with the interior of the airbag via the vent hole, and the outflow resistance mechanism may provide resistance to the outflow of gas from the airbag to the sub-chamber. By providing a sub-chamber, it is possible to effectively prevent gas from leaking from the airbag before landing. [Brief explanation of the drawings]

[0009] [Figure 1]1A and 1B are diagrams showing the configuration of the drone of the embodiment before and after airbag deployment, and illustrating the operation of the vent hole opening mechanism. [Figure 2] 10 is a graph for explaining the effect when a vent hole is provided, in comparison with the effect when no vent hole is provided. [Figure 3] 10 is a diagram showing the configuration of a modified drone after the airbag is deployed, and a graph for explaining the effect of the vent hole. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following describes in detail, with reference to the drawings, a drone as an embodiment of the present invention and its modifications. In addition to the following embodiments and modifications, the present invention can be embodied in various forms that incorporate various modifications and improvements based on the knowledge of those skilled in the art. [Example]

[0011] The drone of the embodiment is shown in a longitudinal cross-section in FIG. 1(a) and a view from below in FIG. 1(b). The longitudinal cross-section in FIG. 1(a) is a cross-section taken along line aa in FIG. 1(b), and the internal structure is omitted from the cross-section. As shown in these figures, the drone includes a cylindrical main body 10, four arms 12 extending radially from the upper part of the main body 10, rotors 14 disposed at the tip of each of the arms 12, a doughnut-shaped airbag device 16 disposed at the lower part of the main body 10, a parachute device 18 disposed at the center of the upper part, and a grounding ring 20 disposed below the main body 10. The airbag device 16 includes a folded airbag 22 and an inflator 24 for inflating the airbag 22 with gas. The parachute device 18 includes a folded parachute 26 and a deployer 28 for deploying the parachute 26.

[0012] If an abnormality occurs during flight, such as the rotor 14 stopping rotation, this drone deploys a parachute 26 to slow its descent and stabilize its posture, and deploys an airbag 22 to cushion the impact of landing. With the parachute 26 and airbag 22 deployed, the drone appears as shown in the longitudinal cross-section of FIG. 1(c) and the transverse cross-section of FIG. 1(d). The cross-section of FIG. 1(d) is a view from below of the dd section of FIG. 1(c), located midway between the airbag 22 in the vertical direction. The main body of the parachute 26 is omitted, and only the string is shown. As can be seen from these figures, the airbag 22 deploys in a generally doughnut shape, supported from above by the ground ring 20. The lower part of the airbag 22 (shown by the bold line in FIG. 1(c)) is made of thicker fabric to prevent damage to the airbag 22 upon landing.

[0013] The inflator 24 is a typical type that deploys the airbag 22 by releasing compressed gas into the airbag 22. As a result, a certain amount of pressure is created inside the deployed airbag 22. To maintain the proper shape of the deployed airbag 22, six tethers 30 are arranged around the circumference inside the airbag 22, connecting the upper and lower parts. Due to the pressure inside the airbag 22, the tethers 30 are under tension.

[0014] In this drone, to prevent the drone from bouncing when it lands with the airbag 22 deployed, vent holes 32 that allow the gas inside to escape when it lands are provided in the airbag 22. The vent holes 32 are generally oval in shape, and two are provided on the top of the airbag 22, positioned point-symmetrically about the center.

[0015] 1(e), which shows an enlarged view of the area where the vent hole 32 is provided, i.e., the area circled in FIG. 1(c), a reinforcing ring 34 is attached to the front side of the airbag 22 for reinforcement at the vent hole 32. When the airbag 22 is deployed, the vent hole 32 is closed from the inside with a strap 36. One end of the strap 36 is connected to the lower and other ends of the airbag 22, i.e., to portions that face each other, and functions similarly to the tether 30. More specifically, a generally rectangular fastener 38 with a narrow vertical width is provided on the inner peripheral portion of the airbag 22 relative to the vent hole 32. This fastener 38 is attached to the airbag 22 so that an upper side 38a of the rectangular shape is located outside the airbag 22 and a lower side 38b is located inside the airbag 22. The strap 36 passes between the lower edge portion 38b and the fabric of the airbag 22, and the portion between the lower edge portion 38b and the other end covers the inside of the vent hole 32. When the airbag 22 is deployed, the strap 36 is pulled by the action of the gas pressure inside the airbag, and closes the vent hole 32.

[0016] When the airbag 22 lands in a deployed state, the airbag 22 deforms in a direction that reduces its vertical dimension. This deformation upon landing causes the straps 36 to loosen, as shown in FIG. 1(f), and the pressure inside the airbag 22 increases, causing the straps 36 to protrude outward through the vent holes 32. This protrusion opens the vent holes 32, allowing the gas inside to flow outward. This drone has such a mechanism, that is, a vent hole opening mechanism that opens the vent holes 32 by the deformation of the airbag 22 upon landing.

[0017] According to the above-described vent hole opening mechanism, before opening, the gas pressure fastens the strap 36 to the inner surface of the airbag 22, sealing the gas inside the airbag 22, but the sealing is weak. Simply put, there is a high possibility of some gas leakage. Taking this into consideration, it is possible to reduce leakage by setting the temperature of the gas immediately after deployment of the airbag 22 to be lower than the ambient temperature, and then gradually increasing the temperature of the gas inside the airbag 22 to approach the ambient temperature, thereby increasing the pressure inside the airbag 22. Generally, the inflator 24 is designed to adiabatically expand compressed gas, so the gas is heated to a certain degree before being released into the airbag 22. By adjusting the degree of heating, it is possible to adjust the temperature of the gas inside the airbag 22 immediately after deployment.

[0018] The effect of providing the vent holes 32 will be explained below in comparison with the effect when the vent holes 32 are not provided. FIG. 2(a) is a graph showing changes in the gas pressure (hereinafter sometimes referred to as "internal pressure") inside the airbag 22, the drone's falling speed, and the drone's altitude when the vent holes 32 are not provided. If the drone starts to fall at time t0 and the airbag 22 starts to deploy immediately thereafter at time t1, as shown in the graph, the pressure inside the airbag 22 is maintained at a predetermined pressure until time t2 when the airbag 22 contacts the ground, while the drone's falling speed increases and the drone's altitude, i.e., the drone's distance from the ground, decreases. After the airbag 22 contacts the ground, i.e., after landing, the internal pressure of the airbag 22 rises sharply, causing the drone to bounce off the ground.

[0019] 2(b) is a graph showing the changes in the internal pressure of the airbag 22 of a drone equipped with the above-described vent hole 32 and vent hole opening mechanism, i.e., the drone of the embodiment, the falling speed of the drone, and the altitude of the drone. As this graph shows, in the drone of the embodiment, at time t3 immediately after the airbag 22 contacts the ground, the airbag 22 deforms and opens the vent hole 32, thereby suppressing the rise in the internal pressure of the airbag 22, suppressing the drone from bouncing, and reducing the falling speed of the drone. Modified Example

[0020] As shown in Figure 3(a), the drone of the modified example is equipped with an airbag 22 similar to that of the drone of the embodiment, but a sub-chamber 40 is attached to the airbag 22. Incidentally, Figure 3(a) is a partial vertical cross-sectional view of the airbag 22 in an expanded state, and the sub-chamber 40, like the airbag 22, has a doughnut shape that surrounds the entire periphery of the drone.

[0021] In this drone, a vent hole 32' is provided in a different position than in the drone of the embodiment, and the interior of the sub-chamber 40 is in communication with the interior of the airbag 22 via this vent hole 32'. In this drone, an outflow resistance imparting mechanism 42 is provided on the sub-chamber 40 side of the vent hole 32', which imparts resistance to the outflow of gas passing through the vent hole 32' from the airbag 22 to the sub-chamber 40. Simply put, this outflow resistance imparting mechanism 42 is like a restrictor (orifice) with a relatively small flow path area.

[0022] In this drone, the inflator 24 deploys the airbag 22 and the sub-chamber 40. When a drone with the airbag 22 and sub-chamber 40 deployed falls, the airbag 22 deforms when the lower part of the airbag 22 touches the ground. This deformation causes the gas inside the airbag 22 to flow through the vent hole 32' and into the sub-chamber 40. The outflow resistance mechanism 42 provides resistance to this outflow. At this time, the internal pressure of the airbag 22 and the internal pressure of the sub-chamber 40 change as shown in the graph in FIG. 3(b). More specifically, at time t3 immediately after the airbag 22 touches the ground, the airbag 22 deforms, causing the internal pressure of the airbag 22 to rise. As shown by the dashed line, the internal pressure of the sub-chamber 40 also rises. As can be seen from a comparison with the graph in FIG. 2(a), which shows the change in the internal pressure of an airbag 22 without a vent hole 32, the increase in the internal pressure of the airbag 22 is significantly suppressed in this drone. As a result, the drone's bounce is reduced.

[0023] Although this drone is less effective at preventing the drone from bouncing than the drones of the above-mentioned embodiments, it can adequately prevent the gas from leaking from the airbag 22 during the fall as described above. [Explanation of symbols]

[0024] 10: Main body 12: Arm 14: Rotor 16: Airbag device 18: Parachute device 20: Grounding ring 22: Airbag 24: Inflator 26: Parachute 28: Deployer 30: Tether 32, 32': Vent hole 34: Reinforcement ring 36: Strap 38: Fastener 40: Subchamber 42: Outflow resistance mechanism

Claims

[Claim 1] A drone equipped with an airbag that deploys downward when falling, and the airbag is provided with a vent hole that allows the internal gas to escape when landing, a vent hole opening mechanism provided inside the airbag, the ends of which are connected to upper and lower opposing portions of the airbag, respectively, and which has a strap that closes the vent hole in a tensioned state due to the gas pressure inside the airbag, the strap loosening due to deformation of the airbag when the vehicle lands, thereby opening the vent hole; an inflator that deploys the airbag by adiabatically expanding compressed gas into the airbag, The drone is configured such that the inflator heats the gas released into the airbag to such an extent that the temperature of the gas in the airbag immediately after the airbag is deployed is lower than the ambient temperature.

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