JPH10203489A - Landing gear for helicopter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve roll rigidity while leaving a merit of an independent suspension, in the case that a right/left leg of a helicopter is a trailing arm type of independent suspension system. SOLUTION: Between base ends 13 of a right/left trailing arm 12 is connected by a cross tube 10. A spherical bearing 11 in the vicinity of both ends of an axial line 16 of the cross tube 10 is fixed to an airframe of a helicopter. From outward of the spherical bearing 11 of the axial line 16, the trailing arm 12 is extended to downward of the air frame, a wheel 15 is mounted at a tip end 14. In a part of an axle 18, a shock strut 20 is provided between the airframe, damping is performed in the case of swivel displacement of the trailing arm 12 about the axial line 16. The swivel displacement, through the cross tube 10, is transmitted to a certain degree to the other trailing arm 12, to be adjusted so as to prevent only one of the arms 12 from large sinking.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a landing gear for a helicopter for suspending wheels of the helicopter independently of each other.

[0002]

2. Description of the Related Art FIG. 11 shows an independent suspension structure of a conventional helicopter landing gear. The base end 3 of the trailing arm 2 is fixed to both sides of the body 1 of the helicopter. The trailing arm 2 extends obliquely downward from the base end 3, and a wheel 5 is attached to the tip end 4. The left and right trailing arms 2 have an axis 6 connecting between the base ends 3.
, And can be swingably displaced left and right independently. As described above, when the left and right legs of the airframe 1 are independently suspended, it is possible to absorb irregularities at the landing point during landing or the like, and improve the pilot rating. Trailing
Prior art relating to a suspension system using an arm is disclosed for automobiles, for example, in Japanese Utility Model Laid-Open No. 2-204 and Japanese Patent Laid-Open No. 5-116516.

[0003]

As shown in FIG.
In the case where the left and right trailing arms 2 are independently movable legs, if the loads supported by the left and right legs are uneven, the vertical position of the wheel 5 is different, and a roll angle is generated. This roll angle is generated when the helicopter is slowly landing, when landing on a slope inclined left or right, or when turning while taxiing, and may deteriorate the pilot rating. This tendency is remarkable especially in a leg with a large stroke with a high sink rate and a low load multiple by increasing the swing displacement of the trailing arm.

In the prior art of Japanese Utility Model Laid-Open No. 2-204, the left and right wheels are connected by an axle arm, and the range of the stroke in which the left and right wheels can move independently is narrow. Japanese Patent Laid-Open No. 5-
In the prior art of 116516, although the spring characteristics can be easily adjusted by using a torsion bar spring for each wheel, the left and right wheels are completely independent, and when applied to a helicopter, the above-described problem occurs. Inevitable.

SUMMARY OF THE INVENTION An object of the present invention is to make it possible to reduce the difference between the swing displacement angles of the left and right trailing arms while maintaining the characteristics of an independent suspension, and to reduce the pilot rating of a helicopter landing gear. It is to provide.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a helicopter has two sides which extend diagonally downward with bases on both sides thereof, wheels are mounted on the ends, and swing displacements are made independently about an axis connecting the bases. A helicopter landing gear comprising: a pair of possible trailing arms; and a torsion spring connecting between the base ends of each trailing arm. According to the present invention, since the base ends of the trailing arms on both sides of the fuselage are connected by a torsion spring, the torsional spring is subjected to torsional deformation by the swing displacement of each trailing arm. The torsion spring transmits torque from one trailing arm to the other while causing some torsional deformation. Since a part of the swing displacement of one trailing arm is transmitted to the other, the difference between the swing displacements can be reduced and the inclination can be reduced.

Further, the present invention is characterized in that a cross tube provided between the base ends of the trailing arms is used as the torsion spring. According to the present invention, since the base end of the trailing arm is connected by a cross tube and used as a torsion spring, the angle difference of the swing displacement can be reduced with a simple structure.

The torsion spring of the present invention is housed in a cross tube provided between the base ends of the trailing arms. According to the present invention, the proximal end of each trailing arm is connected by a torsion spring provided inside the cross tube. Since the torsion spring is housed in the cross tube, a soft spring having a small spring constant against torsional deformation can be used.

Further, the torsion spring of the present invention is housed in a cross tube provided between the base ends of the trailing arms, and the torsion spring and the cross tube are connected in series. According to the present invention, the vicinity of the connection of the cross tube with the base end of the trailing arm has a plurality of layers in the radial direction, and the joints between the layers are alternately formed inward and outward in the axial direction. With a folded structure, the length of the tube can be increased substantially with a short length of tube, and the rigidity of the swinging movement between the trailing arms can be maintained sufficiently while increasing the roll rigidity. be able to.

[0010]

FIG. 1 shows a construction of a landing gear for a helicopter having a connecting structure of a trailing arm according to a first embodiment of the present invention. The cross tube 10, which is a cylindrical tube, is rotatably mounted on a helicopter body (not shown) so as to be rotatable by spherical bearings 11 provided near both ends in the axial direction. The proximal end 13 of the trailing arm 12 is attached to the joint 17 at both ends in the axial direction of the cross tube 10. A wheel 15 is attached to the distal end 14 of the trailing arm 12 and is swingable about an axis 16 of the cross tube 10. Wheels 15 are mounted on the tip 14 of the trailing arm 12 by an axle 18 parallel to the axis 16 of the cross tube 10. A shock strut 20 is provided between the attachment portion and the body, and performs a damping action when the trailing arm 12 swings.

FIGS. 2 and 3 are partial side and front views, respectively, associated with the trailing arm 12 of the embodiment of FIG. The shock strut 20 is attached to the mounting portion 2
1 attaches to the body 22 of the helicopter. When a load is applied to the wheel 15, the trailing arm 12 swings about the base end 13. The shock strut 20 contracts and absorbs the shock load until it reaches a rest position within the range from the most extended position to the most compressed position. If there is a difference in the displacement angle between the left and right trailing arms 12 during such swinging displacement of the trailing arm 12, a torsional torque is generated in the cross tube 10.

FIG. 4 is a side view showing the vicinity of the connecting portion 17, and FIG. 5 is a sectional view taken along the line VV in FIG. The proximal end 13 of the trailing arm 12 is attached to the connecting portions 17 at both ends of the cross tube 10 with a space 23 left therebetween. The proximal end 13 and the cross tube 10 have splines inside and outside the axis 16, respectively, and are interconnected via spline joints 23a and 23b. The inside of the axially outer end of the cross tube 10 is sealed by an inner cap 24. A lock nut 25 is screwed onto the outside of the cross tube 10 from the axially outer end side, and the inner cap 24 and the cross tube 10 are fixed using bolts 26 and nuts 27. The inner end of the base end 13 is a spherical bearing 1
1 is pressed against the outer end.

The swinging displacement of the trailing arm 12 on one side about the axis 16 is
a, 23b directly to the cross tube 10. The cross tube 10 acts as a torsion spring and transmits torque to the trailing arm 12 on the other side of the axis 16. Trailing arm 12 on the other side
Performs oscillating displacement according to the transmitted torque. With the cross tube 10 interposed as a torsion spring, the left and right legs can reduce the angular difference in the swing displacement while maintaining the characteristics of independent suspension.

FIG. 6 shows the principle of the shock strut 20.
Fig. 2 shows a typical configuration. In the piston 30, there is an orifice 31 and
And the free piston 32 are stored in the cylinder 20a.
Oil 33 in the space between
Is filled. From the free piston 32 of the piston 30
Is filled with gas 34 in the closed space on the tip side
The position of the piston 32 depends on the pressure P of the gas 34 and the γ of the volume V.
Product PV with power It changes based on the relationship where γ is constant.
Here, γ is a polytropic index. Oil 33 side
Although the volume is almost the same,
Time delay when flowing to the free piston 32 side
I will.

FIG. 7 shows the operating characteristics of the shock strut 20 shown in FIG. The relationship between the load and the stroke as shown by the solid line is obtained by combining the contribution by the gas 34 shown by the one-dot chain line and the contribution by the oil 33 shown by the two-dot chain line. If the load W is reduced, the stroke required to absorb the same impact energy becomes longer. If the load W is small, the impact force applied to the body of the helicopter during landing or the like is small, which is preferable. However, if the vehicle leans to one side during landing on uneven terrain or the like, the inclination is promoted and the pilot rating deteriorates. In such a leg having a high squat rate and a low load multiple with a large stroke, the cross displacement of the left and right trailing arms 12 is transmitted to a certain extent by the cross tube 10 as in the embodiment of FIG. It is preferable to reduce the difference between the angles of displacement to reduce the roll angle of the fuselage.

FIG. 8 shows the construction of a landing gear for helicopter having a trailing arm connection structure according to a second embodiment of the present invention. It should be noted in this embodiment that the torque tube is provided inside the cross tube 10 as a torsion spring.
Tube 35 is provided, and cross tube 10 is not used for torque transmission. The proximal end 13 of the trailing arm 12 is rotatable on a sleeve 36 mounted on the outer peripheral side of the cross tube 10. Axis 16
The swing displacement of the trailing arm 12 around
The torque is transmitted to the torque tube 35 via the outer cap 37. A connecting portion 38 for performing spline connection or protruding tooth connection is provided between the outer cap 37 and the proximal end 13, and a connecting portion 39 for performing spline connection is provided between the outer cap 37 and the torque tube 35. .

FIG. 9 shows a structure of a connecting portion 40 for connecting both ends of the torque tube 35 and the outer cap 37 by spherical splines. According to such a spherical spline connection, the influence of the deflection of the cross tube 10 when the helicopter lands can be absorbed. Although not shown, the deflection of the cross tube 10 at the time of landing can also be absorbed by dividing the torque tube 35 into two parts near the center and connecting them with a universal joint or the like.

FIG. 10 shows the construction of a landing gear for helicopter having a trailing arm connection structure according to a third embodiment of the present invention. It should be noted in this embodiment that the joint between the cross tube 10 and the trailing arm 12 has a quadruple tube structure. The quadruple tube includes an innermost inner tube 41, an outer inner tube 42, a cross tube 10, and a proximal end 13 of the trailing arm 12 as an outermost layer. A sleeve 43 is interposed between the inner peripheral surface of the proximal end 13 of the trailing arm 12 and the outer peripheral surface of the cross tube 10, and the proximal end 13 is rotatable. Proximal end 13 of trailing arm 12
The inner pipe 41 is connected to the inner pipe 41 by an outer cap 44 provided at the outermost part of the axis 16. The connecting portion 45 between the base end 13 of the trailing arm 12 and the outer cap 44 is
It is mechanically connected by a spline connection or a protruding tooth connection. Joint 46 between outer cap 44 and inner tube 41
Are mechanically joined by a spline connection. The end surfaces of the cross tube 10 and the inner cylinder 42 are joined by bolts 47 and nuts 48. The inner tube 41 and the inner tube 42 are spline-connected or riveted at a connecting portion 49 closer to the inside of the axis 16. A lock nut 50 is provided at the outermost end of the axis 16, and fixes the outer cap 44.

The swinging displacement of the trailing arm 12 is transmitted from the base end 13 of the trailing arm 12 to the inner tube 41 by a connecting portion having a four-tube structure as shown in FIG. From the axis 1 of the cross tube 10
It is transmitted to the outer end faces in six directions. The torque transmitted from the other end of the axis 16 via the cross tube 10 is transmitted from the end face of the cross tube 10 to the inner cylinder 42, and further transmitted from the inner tube 41 to the proximal end 13 of the trailing arm 12. You. The portion that contributes to the effective torsion length has a quadruple tube structure, and can be extended in substantial length to reduce torsional rigidity and ease restrictions due to the width of the helicopter body. Further, the influence of the deflection of the cross tube 10 when the helicopter lands can be eliminated.

[0020]

As described above, according to the present invention, the base ends of the trailing arms, which can swing independently on both sides of the body, are connected by a torsion spring, and the swinging of one trailing arm is performed. The displacement can be partially transmitted to the other trailing arm to prevent the roll angle from occurring. By connecting with a soft torsion spring having a small spring constant, it is possible to combine the improvement of roll rigidity and the goodness of independent suspension.

Further, according to the present invention, since the cross tube is used as a torsion spring, a space for mounting can be reduced and an increase in weight can be suppressed.

Further, according to the present invention, since the connection between the trailing arms is performed by the torsion spring provided in the cross tube, even if the spring constant of the inner torsion spring is reduced, the outer cross tube is sufficient. Can be protected. The strength of the cross tube can be designed separately from the spring design.

Further, according to the present invention, the length of the cross tube near the connection with the trailing arm base end can be substantially increased by the folded structure, so that the overall spring constant is reduced. However, the independence of each trailing arm can be increased. cross·
Tube strength can be designed separately from spring design.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a trailing arm connection structure of a helicopter landing gear according to a first embodiment of the present invention.

FIG. 2 is a side view of the embodiment of FIG.

FIG. 3 is a partial front view of the embodiment of FIG.

FIG. 4 is a partial side view of the embodiment of FIG.

FIG. 5 is a cross-sectional view taken along the line VV of FIG. 4;

FIG. 6 is a cross-sectional view showing a basic configuration of a shock strut 20 used in the embodiment of FIG.

FIG. 7 is a graph showing operating characteristics of the shock strut 20 of FIG.

FIG. 8 is a partial front sectional view of a second embodiment of the present invention.

FIG. 9 is a partial cross-sectional view showing a configuration for absorbing the influence of the deflection of the cross tube in the embodiment of FIG. 8;

FIG. 10 is a partial front sectional view of a third embodiment of the present invention.

FIG. 11 is a schematic front view of a conventional helicopter landing gear.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Cross tube 11 Spherical bearing 12 Trailing arm 13 Base end 14 Tip 15 Wheel 16 Axis 17, 38, 39, 40, 45, 46, 49 Connection part 18 Axle 20 Shock strut 22 Body 23a, 23b Spline connection Part 24 Inner cap 30 Piston 31 Orifice 32 Free piston 35 Torque tube 36, 43 Sleeve 37, 44 Outer cap 41 Inner pipe 42 Inner cylinder

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tsutomu Fujigaki 1 Kawasaki-cho, Kakamigahara-shi, Gifu Pref.

Claims (4)

[Claims] 1. With both sides of a helicopter body as base ends,
A pair of trailing arms that extend diagonally downward, have wheels attached to their ends, and can swing independently about an axis connecting the base ends, and a torsion that connects the base ends of each trailing arm. A landing gear for a helicopter, comprising a spring. 2. The helicopter landing gear according to claim 1, wherein a cross tube provided between the base ends of the trailing arms is used as the torsion spring. 3. The helicopter landing gear according to claim 1, wherein said torsion spring is housed in a cross tube provided between base ends of each trailing arm. 4. The torsion spring is housed in a cross tube provided between base ends of each trailing arm, and the torsion spring and the cross tube are connected in series. Helicopter landing gear.