JPH0313111B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for easily and uniformly forming a gap between a propeller tip and an inner circumferential surface of a duct in a duct propeller.

[Prior art]

BACKGROUND ART Conventionally, propellers have generally been used as propulsion devices for hovercrafts, and some types of hovercrafts use so-called duct propellers in which a propeller is disposed in a cylindrical duct.

However, the gap between the tip of the propeller and the inner peripheral surface of the duct is only a few percent of the diameter of the propeller for performance reasons. The gap l between duct 1 and duct 2 is several mm.

This makes it extremely difficult to manufacture and center the duct.

[Object of the Invention] An object of the present invention is to easily and uniformly form a gap between the tip of a propeller and the inner peripheral surface of a duct.

[Structure of the invention]

A method for forming a gap in a duct propeller according to the present invention that can achieve the above object is to apply an extra gap adjustment material to the inner circumferential surface of the duct, and then attach a propeller or a propeller to a rotating shaft that has the same axis as the duct. Attach a support member made of a member of the same diameter, then attach a cutter to the tip of the support member so as to protrude by a predetermined length, and then cut the gap adjustment material into a predetermined shape by rotating the cutter. It is characterized by what it does.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 2 denotes a duct, and an extra gap adjusting material 4 made of, for example, foamed plastic is attached to the inner wall surface 3 of the duct 2 as shown by the two-dot broken line. This gap adjustment material 4 is arranged along the inner circumference of the duct 2 facing the tip of the propeller 1, and its width W is 2 to 2 of the width w of the propeller 1, that is, the width w in the direction of the axis 10. About 10 times,
The pre-filling height is set to be slightly higher than the final forming height.

Next, a support member 11 is attached to the rotating shaft 5 having the same axis 10 as the duct 2. The support member 11 may be the propeller 1 or a member having the same diameter as the propeller 1.

Next, a cutter 6 is attached to the tip of the support member 11.
Attach by sticking out the specified length. The shape of the tip 7 of this cutter 6 is matched to the final shape of the gap adjustment material 4.

Next, when the rotating shaft 5 is rotated, the cutter 6 rotates together with the support member 11, and the cutter 6 cuts off the excess portion of the gap adjustment material 4. The portion of the gap adjusting material 4 that the cutter 6 hits is formed into a predetermined shape as shown by the solid line.

By the way, the part where the cutter 6 does not hit remains as shown by the dotted line, but since this part does not require as much precision as on the left, it is shaped by hand as shown by the solid line.

In addition, by making the tip 7 of the cutter 6 into a whole shape rather than a partial shape, manual work becomes unnecessary.

As a result of the above, the gap l between the tip of the support member 11 and the formed gap adjusting material 4 shown by the solid line can be easily and uniformly processed.

After processing the gap adjustment material 4, the support member 11 is removed from the rotating shaft 5, and the propeller 1 is attached in its place.

〔Effect of the invention〕

As described above, the present invention provides an arrangement in which a clearance adjustment material is added to the inner circumferential surface of the duct, and then a support made of a propeller or a member having the same diameter as the propeller is attached to a rotating shaft that has the same axis as the duct. The member is attached, and then the cutter at the tip of the support member is attached by protruding by a predetermined length, and then the cutter is rotated to cut the gap adjustment material into a predetermined shape, so that the propeller can be cut. It becomes possible to easily and uniformly form a gap between the tip and the inner peripheral surface of the duct.

[Brief explanation of the drawing]

FIG. 1 is an explanatory view showing a method for forming a gap in a duct propeller according to the present invention, and FIG. 2 is a sectional view of the duct propeller. 1... Propeller, 2... Duct, 3... Inner peripheral surface, 4... Gap adjustment material, 5... Rotating shaft, 6... Cutter, 7... Tip, 10... Shaft core, 11... Support Element.

Claims (1)

[Claims] 1. Apply extra gap adjustment material to the inner peripheral surface of the duct, then attach a support member made of a propeller or a member with the same diameter as the propeller to the rotating shaft that has the same axis as the duct, and then attach the support member made of a propeller or a member with the same diameter as the propeller. A method for forming a gap in a duct propeller, wherein a cutter is attached to the tip of the propeller so as to protrude by a predetermined length, and then the cutter is rotated to cut the gap adjustment material into a predetermined shape.