Helicopter

Abstract

The airframe of this helicopter is separated into a first part and a second part. A power device is disposed in the first part. A tail rotor is disposed at an end of the second part opposite to the first part. A first shaft is disposed in the first part, and rotational driving force of the power device is transmitted to the first shaft. A first adapter is coupled to the first shaft. A second adapter is coupled to the first adapter. A second shaft is coupled to the second adapter and the tail rotor, and is disposed in the second part. A first bearing is disposed radially outward of the first adapter and rotatably supports the first adapter, or is disposed adjacent to the first adapter and rotatably supports the first shaft. A second bearing is disposed radially outward of the second adapter and rotatably supports the second adapter, or is disposed adjacent to the second adapter and rotatably supports the second shaft.

Claims

1. A helicopter comprising: a body separated into a first part and a second part; a power unit disposed in the first part; a tail rotor disposed at the end of the second part opposite to the first part; a first shaft disposed within the first part and having a first end located near the power unit and a second end located far from the power unit, and to which the rotational driving force of the power unit is transmitted; a first adapter connected to the second end of the first shaft; a second adapter disposed on the opposite side of the first shaft, with the first adapter in between, and connected to the first adapter; a second shaft disposed within the second part and having a third end connected to the second adapter and a fourth end connected to the tail rotor; and a first bearing disposed radially outside the first adapter and rotatably supporting the first adapter, or disposed adjacent to the first adapter and rotatably supporting the first shaft. A helicopter comprising a second bearing positioned radially outward of the second adapter and rotatably supporting the second adapter, or positioned adjacent to the second adapter and rotatably supporting the second shaft.

2. The helicopter according to claim 1, wherein the first adapter includes a spline hole, the second adapter includes a spline shaft spline-coupled to the spline hole, the first adapter includes a first protrusion extending circumferentially on the inner circumference of the first adapter, the first protrusion projecting radially to a height greater than half the difference between the small spline diameter of the spline hole and the large spline diameter of the spline hole, the second adapter includes an opposing outer peripheral surface facing radially to the first protrusion, and the radial clearance between the first protrusion and the opposing outer peripheral surface is less than the difference between the small spline diameter of the spline hole and the small spline diameter of the spline shaft, and less than the difference between the large spline diameter of the spline hole and the large spline diameter of the spline shaft.

3. The helicopter according to claim 1, wherein the first adapter includes a spline hole, the second adapter includes a spline shaft spline-coupled to the spline hole, the second adapter includes a second protrusion extending circumferentially on its outer circumference, the second protrusion projecting radially to a height greater than half the difference between the small spline diameter of the spline shaft and the large spline diameter of the spline shaft, the first adapter includes an opposing inner circumferential surface portion radially opposite to the second protrusion, and the radial clearance between the second protrusion and the opposing inner circumferential surface portion is smaller than the difference between the large spline diameter of the spline hole and the large spline diameter of the spline shaft, and smaller than the difference between the small spline diameter of the spline hole and the small spline diameter of the spline shaft.

4. A helicopter according to claim 1, wherein the first adapter includes a spline shaft, the second adapter includes a spline hole spline-coupled to the spline shaft, the first adapter includes a first protrusion extending circumferentially on the outer circumference of the first adapter, the first protrusion projecting radially to a height greater than half the difference between the small spline diameter of the spline shaft and the large spline diameter of the spline shaft, the second adapter includes an opposing inner circumferential surface portion radially opposite to the first protrusion, the radial clearance between the first protrusion and the opposing inner circumferential surface portion is less than the difference between the large spline diameter of the spline hole and the large spline diameter of the spline shaft, and less than the difference between the small spline diameter of the spline hole and the small spline diameter of the spline shaft.

5. A helicopter according to claim 1, wherein the first adapter includes a spline shaft, the second adapter includes a spline hole spline-coupled to the spline shaft, the second adapter includes a second protrusion extending circumferentially on the inner circumference of the second adapter, the second protrusion projecting radially to a height greater than half the difference between the small spline diameter of the spline hole and the large spline diameter of the spline hole, the first adapter includes an opposing outer peripheral surface facing radially to the second protrusion, the radial clearance between the second protrusion and the opposing outer peripheral surface is less than the difference between the small spline diameter of the spline hole and the small spline diameter of the spline shaft, and less than the difference between the large spline diameter of the spline hole and the large spline diameter of the spline shaft.

6. A helicopter according to any one of claims 1 to 5, wherein the first adapter includes a first connecting portion connected to the second end of the first shaft and a first small-diameter portion having an outer diameter smaller than the outer diameter of the first connecting portion, and the first bearing is disposed radially outward of the first small-diameter portion.

7. A helicopter according to any one of claims 1 to 5, wherein the second adapter includes a second connecting portion connected to the third end of the second shaft and a second small-diameter portion having an outer diameter smaller than the outer diameter of the second connecting portion, and the second bearing is disposed radially outward of the second small-diameter portion.

8. The helicopter according to claim 1, wherein the first adapter includes a spline hole, the second adapter includes a spline shaft spline-coupled to the spline hole, the first adapter includes a first connecting portion connected to the second end of the first shaft, and a first small-diameter portion having an outer diameter smaller than the outer diameter of the first connecting portion, the first bearing is positioned radially outward of the first small-diameter portion, the first small-diameter portion includes the spline hole, the second adapter includes a second connecting portion connected to the third end of the second shaft, a second small-diameter portion having an outer diameter smaller than the outer diameter of the second connecting portion, and a third small-diameter portion having an outer diameter smaller than the outer diameter of the second small-diameter portion, the second bearing is positioned radially outward of the second small-diameter portion, and the third small-diameter portion includes the spline shaft.

9. The helicopter according to claim 1, wherein the first adapter includes a spline shaft, the second adapter includes a spline hole spline-coupled to the spline shaft, the first adapter includes a first connecting portion connected to the second end of the first shaft, a first small-diameter portion having an outer diameter smaller than the outer diameter of the first connecting portion, and a second small-diameter portion having an outer diameter smaller than the outer diameter of the first small-diameter portion, the first bearing is positioned radially outward of the first small-diameter portion, the second small-diameter portion includes the spline shaft, the second adapter includes a second connecting portion connected to the third end of the second shaft, and a third small-diameter portion having an outer diameter smaller than the outer diameter of the second connecting portion, the second bearing is positioned radially outward of the third small-diameter portion, and the third small-diameter portion includes the spline hole.

10. A helicopter according to any one of claims 1 to 5, 8 and 9, comprising a first rubber sleeve having a circumferentially extending annular groove, the annular groove partially housing the first bearing, wherein the first bearing rotatably supports the first adapter or the first shaft via the first rubber sleeve.

11. A helicopter according to any one of claims 1 to 5, 8 and 9, comprising a second rubber sleeve having a circumferentially extending annular groove, the annular groove partially housing the second bearing, wherein the second bearing rotatably supports the second adapter or the second shaft via the second rubber sleeve.

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