JP2573826B2 - Small helicopter landing gear - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a landing apparatus for a radio guided small unmanned helicopter used for spraying a medicine and the like, and particularly when a helicopter in flight is suddenly landed. It is an object of the present invention to provide a small and high-performance landing gear capable of effectively buffering an impact on an airframe.

[Conventional technology and its problems]

Conventionally, a landing gear of a small helicopter is provided with a pair of left and right landing sleds supported by a number of rigid supports at the bottom of the machine frame, and a buffer between the landing sled and the machine frame is provided as necessary. Provision of a device has been made (eg, US Pat. No. 2,318,259).

However, the helicopter landing gear requires a non-linear characteristic to be small and capable of absorbing a large load, and is usually constituted by a shock absorbing mechanism consisting of a link mechanism and a spring between the body frame and the landing sled. In addition, the weight of the landing gear is large and the structure is complicated, so that an increase in manufacturing cost cannot be avoided.

[Object of the Invention, Outline of Configuration]

The present invention has been made to solve the above problems,
An object of the present invention is to provide a landing gear having a simple structure, light weight, and capable of absorbing a large impact.

The landing apparatus for a small helicopter according to the present invention is a landing apparatus for a small helicopter in which a pair of left and right landing sleds are connected to a supporting leg provided at a lower portion of the fuselage via a fixing tool. It is formed of a spring material in a continuously extending plate shape and projects outward from the fuselage and is bent downward, and the bending portion is configured to be able to bend and extend with the thickness direction of the support leg in the vertical direction.

[Action]

When the aircraft descends rapidly and comes into contact with the ground, the free end of the plate-like spring material that forms the support leg tries to slide outward and expands, but an accretion sled is provided at the lower end of the support leg in the front-rear direction. Yes,
This causes resistance to prevent the deformation, so that the deformation is not relatively deformed at first, and when the landing sled starts to slide in the left-right direction, the spring characteristic is rapidly softened to obtain a desired non-linear characteristic.

〔Example〕

Hereinafter, the present invention will be described with reference to the illustrated embodiment.
In FIG. 2, reference numeral 1 denotes an airframe of a small helicopter, and FIG. 2 shows a state in which the tail of the airframe is lifted in order to move the airframe 1 manually. At the lower part of the body 1, a pair of left and right steel pipe body frame members 2a, 2a constituting a body frame are arranged in the front-rear direction. A support leg 4 is connected to the body frame members 2a, 2a by a U-bolt 3, and a landing sled 5 is provided at a lower end of the support leg 4 that is curved downward. 6 is a conventionally known main rotor;
Is an auxiliary rotor, 1a is an exhaust silencer provided on the side surface of the fuselage 1 and opened rearward, and 1b is a grill of an engine cooling radiator opened diagonally upward in front of the fuselage. .

The support leg 4 is formed of a spring material in an elongated plate shape extending in the left-right direction of the body 1. The material of the spring material is a steel plate or a fiber reinforced plastic. The support leg 4 is formed so as to protrude outward from the body 1 and bend downward, so that the bending portion can be bent and stretched with the thickness direction being the vertical direction. 3, is supported by a pair of front and rear U-bolts 3 and a connecting piece 8 for connecting the legs of the two U-bolts 3, and is pivotally and longitudinally moved with respect to the body frame members 2a, 2a. Some movement in the direction is allowed. The axial direction of the rotation of the support leg 4 is a direction perpendicular to the plane including the deformation trajectory of the spring material, and is the front-rear direction of the body 1 orthogonal to the paper surface of FIG. The U-bolt 3 and the connecting piece 8 constitute a fixing device for a leg. 3a is a rubber cushion material sandwiched between the body frame member 2a. As described above, the support leg 4 is bridged between the pair of left and right body frame members 2a, 2a, and extends outward from the body frame members 2a, 2a and curves downward.
A circular through hole 4a is provided at the lower end thereof, and an accretion sled 5 formed by bending a steel pipe is inserted therethrough and fastened with a bolt 5a. Curve C in FIG. 4 shows the spring characteristics of this landing gear. In the figure, a curve B shows ideal characteristics of the landing gear for helicopter, and a curve A shows general spring characteristics of the synthetic resin spring. 9 is a wheel rotatably supported on the front end of the landing sled 5.

Therefore, when the impact load is relatively small when the helicopter lands, the leg 4 attempts to open due to the impact load, but relatively large resistance to the lateral movement of the landing sled 5. Therefore, the impact is absorbed only by the elastic deformation of the support leg 4. Also, when the impact at the time of landing is very large, for example, when the landing is as severe as a crash from a height of several meters from the ground, the landing sled 5 slides to the side due to the impact at the time of landing, The leg 4 is elastically deformed and the leg is opened. This movement reduces the coefficient of friction between the landing sled 5 and the ground surface, and furthermore, the force point becomes more distant from the fulcrum as the degree of leg opening increases. As shown by the phantom line, large deformation is easily performed, and the impact during this time is absorbed or consumed by the elastic deformation of the support legs 4 and the frictional resistance between the landing sled 5 and the ground surface. Moreover, the support leg 4 is supported by the fuselage 1 via a fixing tool composed of the U bolt 3 and the connecting piece 8, and is fixed to the fuselage 1 in a direction perpendicular to the plane including the deformation trajectory of the spring material (of the fuselage 1). Since it is rotatable about the longitudinal axis (in the front-rear direction) and is movable in the longitudinal direction of the support leg 4, there are the following advantages. That is, since the support leg 4 can rotate at the fixed portion, the stress generated in the support leg 4 due to the bending of the support leg 4 during landing can be reduced. In addition, when a load is applied to the support leg 4 along the longitudinal direction during landing, the load can be released by moving the support leg 4, so that the stress generated in the support leg 4 can be reduced. it can.

Further, the support leg 4 is a cushion material between the support frame 4 and the body frame member 2a.
3a is supported in a state where it is sandwiched, so that it is rotated when the support 4 is deformed or when a load is applied between the body 1 and the support 4 along the longitudinal direction of the support 4. In any case, frictional resistance occurs. That is, since this frictional resistance acts as a damping force and can absorb an impact, the spring reaction force of the support leg 4 can be set smaller by that amount.
Further, the amount of the body jumping up due to the restoration of the spring material can be reduced.

〔The invention's effect〕

As described above, the landing apparatus for a small helicopter according to the present invention is a landing apparatus for a small helicopter in which a pair of left and right landing sleds are connected to a supporting leg provided via a fixing tool at a lower portion of the fuselage. Formed by a spring material into a plate shape extending continuously in the left-right direction of the fuselage, projecting outward from the fuselage and having a shape that bends downward. Therefore, the impact when the aircraft lands can be alleviated by the elastic deformation of the support legs themselves, so that a landing gear having an impact buffering function can be obtained without separately mounting a buffering mechanism. In addition, since the thickness direction of the plate-shaped support leg is the vertical direction, when mounting the load directly under the support leg, move the load closer to the aircraft compared to when the thickness direction of the support leg is the front-rear direction of the aircraft. Can be placed.

Therefore, it is possible to obtain a landing gear having a simple structure, light weight, and non-linear characteristics capable of absorbing a large impact.

Furthermore, there is an advantage that the spring characteristics can be set with a large degree of freedom by forming all of the plate-like supporting legs with a spring material. This is because the spring constant changes by changing the width dimension, thickness, and the like of the plate-shaped support leg.

Furthermore, by employing the configuration of the present invention, when the impact force at the time of landing is large, the support leg can be elastically deformed until the curved portion becomes substantially extended, so that a long cushion stroke can be obtained.

When the bent portion of the support leg is elastically deformed so as to extend, the landing sled moves so as to slide toward the side of the fuselage on the ground surface, and the frictional resistance generated between the landing sled and the ground surface helps to reduce impact. Acts to be. That is, in the landing gear according to the present invention, since the assisting by the frictional resistance is performed over the entire elastic deformation area of the support leg, even a large impact force can be reduced.

In addition, with the structure in which the support legs are formed of the entire spring material, even when the aircraft lands in a state of being inclined forward or backward, the impact can be reduced by elastically deforming the support legs. At this time, the support leg is elastically deformed such that the lower end is displaced in the longitudinal direction of the body and twisted. In many cases, the aircraft lands in such an inclined state when landing while moving forward or backward, and the aircraft is subjected to a front-back impact force in addition to a vertical impact force. However, in the present invention, since the thickness direction of the plate-shaped support leg is set to the vertical direction, the impact force in the front-rear direction of the body is such that the elastic force increases, that is, the width of the plate-shaped support leg with the thickness direction set to the vertical direction. Acting in the direction, the impact force can be reliably reduced even if the forward speed or the reverse speed is high.

In addition, when the fixing members are provided on both sides in the left-right direction of the fuselage, and the supporting legs are rotatably supported around the longitudinal axis of the fuselage, the stress generated in the supporting legs when the supporting legs are bent is reduced. be able to.

In addition, if the fixing device is configured to support the support leg so that the support leg can move in the longitudinal direction, if a load in the longitudinal direction of the support leg is applied between the body and the support leg, the load is released by moving the support leg. Therefore, the stress generated in the support legs can be reduced.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a partially cutaway front view showing a main part of a helicopter, FIG. 2 is a side view of the helicopter, and FIG. FIG. 4 is an enlarged side view of the portion, and FIG. 4 is a characteristic diagram showing characteristics of the shock absorber. 1 ... body, 2a, 2a ... body frame member, 3 ... U bolt,
4 ... support leg, 5 ... landing sled, 8 ... connecting piece.

Claims (3)

(57) [Claims] In a landing apparatus for a small helicopter, a pair of left and right landing sleds are connected to a supporting leg provided at a lower portion of the fuselage via a fixing tool, the supporting leg is formed in a plate shape extending continuously in the horizontal direction of the fuselage. A landing gear for a small helicopter, characterized in that it is formed of a spring material so as to protrude outward from the fuselage and bend downward, and that the bending portion is configured to be able to bend and extend with the thickness direction of the support leg in the vertical direction. . 2. A structure according to claim 1, wherein said fixing means is provided on both sides of said fuselage in the left-right direction, and said supporting legs are rotatably supported around the longitudinal axis of said fuselage.
Item 7. The landing device for a small helicopter according to the above item. 3. The landing apparatus for a small helicopter according to claim 1, wherein the fixing device is structured so as to support the supporting leg so as to be movable in the longitudinal direction.