US20190009873A1

US20190009873A1 - A horizontal shaft rotor and a watercraft having the rotor

Info

Publication number: US20190009873A1
Application number: US16/081,375
Authority: US
Inventors: Masahiko Suzuki
Original assignee: NTN Corp
Current assignee: NTN Corp
Priority date: 2016-03-01
Filing date: 2017-02-22
Publication date: 2019-01-10
Also published as: EP3424811A4; JP2017154576A; EP3424811A1; KR20180120709A; CN108698678A; WO2017150299A1

Abstract

A horizontal shaft rotor comprising a lift-type blade, wherein, in the lift-type blade 1, a front face 3D in a flow receiving direction is a large arcuate bulging face in a string direction, a rear face 3E in a discharge direction is made smaller than the bulge of the front face 3D, so that, when the blade rotates, a high speed flow passing along the string direction of the front face from the rear edge portion 3G to the back face 3E direction generates propulsive force.

Description

TECHNICAL FIELD

The present invention relates to a horizontal shaft rotor and a watercraft having the rotor, and more particularly, to a horizontal shaft rotor in which a flow receiving surface of a lift-type blade is largely bulged and a blade tip is inclined to the direction of the flow receiving surface and a watercraft having the rotor.

BACKGROUND OF THE INVENTION

A blade in which the blade tip is inclined to the direction of the flow receiving surface is disclosed for example, in Patent Literature 1.

PRIOR ART

Patent Literature

Patent Literature 1: JP2007-125914A

SUMMARY OF THE INVENTION

Problem to be Solved by the Invention

In the rotor blade disclosed in the above-mentioned Patent Literature 1, for example, when it is used for a ship propulsion machine, water is pushed out by the force of the blade, so that a large power torque for overcoming the resistance of water is required.
It is an object of the present invention to provide a rotor in which a fluid traveling along a circumferential surface of the blade produces a propulsion flow due to a water pressure difference caused by a high-speed flow according to the Coanda effect naturally occurring depended on the shape of the blade by rotating the blade rather than pushing out a fluid with the blade.

Means for Solving the Problems

Special features of the present invention are as follows.
(1) A horizontal shaft rotor comprising a lift-type blade, in the lift-type blade, a front face in a flow receiving direction is a large arcuate bulging face in a string direction, a rear face in a discharge direction is made smaller than the bulge of the front face, when the blade rotates, a high speed flow caused according to the Coanda effect passing along the string direction of the front face from a rear edge portion to a back face direction generates propulsive force.
(2) The horizontal shaft rotor according to (1) above, wherein, in the lift type blade, the back face in the discharge direction at the blade root portion is linear in the string direction and parallel to the rotation direction, the back face is gradually increased inclination to a front face direction from the blade root portion to the maximum string length portion, and from the rear edge portion to a front edge portion.
(3) The horizontal shaft rotor according to (1) or (2) above, wherein, in the lift-type blade, in a side view, a thickness gradually decreases from the blade root portion to a blade tip portion, and the front face gradually inclines to the back face direction from the blade root portion to the blade tip portion.
(4) A watercraft comprising the horizontal shaft rotor according to any one of claims 1 to 3, wherein the horizontal shaft rotor is mounted on a rotor shaft of a rotor housing disposed in the watercraft so that a tip of an inclined portion of a blade is oriented in a bow direction.

Advantages of the Invention

According to the present invention, the following effects can be obtained.
In the invention described in the above (1), since the back face is flat and the front face bulges out like a blade cross-section shape, a high speed flow according to the Coanda effect occurs on the front face in the rotor shaft direction due to the rotation, and this high speed flow passes from the rear edge in the string direction to the back face direction, the propulsive force is generated in the rotor shaft direction as a reaction.
Due to the rotation, the fluid along the front face gathers in the direction of the inclined portion, and gets even faster according to the Coanda effect occurring at the bulging face of the front face in the inclined portion, and passes to the back face direction, the propulsive force in the rotor shaft direction is generated as a reaction.
In the invention described in the above (2), since the back face of the blade root portion of the lift-type blade is straight in the string direction and an angle of attack gradually increases from the blade root portion with the zero angle of attack to the maximum string length portion, a blade tip portion pushes the fluid to make the propulsive force, but since the amount of fluid flowing with high speed along the front face is larger than the amount of fluid to be pushed, the power can be made small.
In the lift-type blade of the invention described in the above (3), in a side view, the thickness gradually decreases from the blade root portion to the blade tip portion, and the front face gradually inclines toward the back face direction from the blade root portion to the blade tip portion, so that the resistance during rotation is small and the fluid along the front face is easy to move to the blade tip direction, the fluid gathered at the inclined portion of the blade tip becomes high speed according to the Coanda effect and flows from the rear edge to the back face direction, the propulsive force is generated as a reaction.
In the invention described in the above (4), since a rotor oriented the tip of the inclined portion of the blade in the bow direction is mounted on the rotor shaft of the rotor housing disposed in the watercraft, when the rotor rotates, the high speed flow moving according to the Coanda effect in the string direction at the front face being the flow receiving surface of the blade passes from the rear edge to the back surface being the discharge direction, the propulsive force is generated as a reaction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of an embodiment of a horizontal shaft rotor of the present invention.

FIG. 2 is a side view of one blade in FIG. 1 viewed from the rear edge side.

FIG. 3 is a plan view of one blade in FIG. 1.

FIG. 4 is a cross-sectional view taken along the line E-E in FIG. 1.

FIG. 5 is a cross-sectional view taken along the line D-D in FIG. 1.

FIG. 6 is a cross-sectional view taken along the line C-C in FIG. 1.

FIG. 7 is a cross-sectional view taken along the line B-B in FIG. 1.

FIG. 8 is a cross-sectional view taken along the line A-A in FIG. 1.

FIG. 9 is a side view of a watercraft having the horizontal shaft rotor of the present invention.

FIG. 10 is a side view showing a partial cross section of the horizontal shaft rotor in FIG. 9.

EMBODIMENTS OF THE INVENTION

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front view of the upstream side (flow receiving side) of the horizontal shaft rotor (hereinafter simply referred to as a rotor) of the present invention, the front face 3D faces, for example, a stern of a ship, and becomes a flow receiving surface that receives an air current in an airplane.
In the rotor 1, a plurality (five in FIG. 1) of lift-type blades (hereinafter simply referred to as blades) 3, 3 are disposed on the peripheral surface of the hub 2.
The blade 3 gradually increases the string length from the blade root portion 3A to the blade tip portion, and the maximum string length portion 3B is set to be as wide as 45 to 50% of a turning radius.
As shown in FIG. 2, a side shape of the blade 3 gradually decreases in thickness from the blade root portion 3A to the blade tip portion, and the front face 3D of the upstream side gradually inclines in the downstream direction (discharge side) from the blade root portion 3A to the blade tip portion.
The tip from the maximum string length portion 3B is an inclined portion 3C, and as shown in FIG. 2, it is inclined at an angle of 30 to 45 degrees to the upstream side (flow receiving side). In addition, in a plan view, as shown in FIG. 3, the maximum string length portion 3B of the back face 3E is set as a base point and the tip is inclined to an orthogonal direction (X arrow).
The back face 3E on the downstream side of the blade 3 is a flat face, as shown in FIGS. 3 to 8, in the blade root portion 3A, the angle of attack is zero with respect to the rotation direction, and gradually increases towards the blade tip portion.
As shown in FIGS. 4 to 8, in the front face 3D that is the upstream side, a central portion of the string bulges out toward the upstream side (rotor shaft direction in the drawings). The degree of this bulging may be, for example, about 15% of the string length in the vicinity of the tip, but the thickness may be increased up to 30% of the string length at the maximum.
In the blade root portion 3A in FIG. 4, from the viewpoint of the strength of the blade 3, the thickness with respect to the string length is about 66% on FIG. 4, but it may be thicker than that.
The thickness gradually becomes thinner towards the blade tip portion. In the maximum string length portion 3B in FIG. 7, the thickness is as thin as about 17% of the maximum string length, and is further thinner toward the inclined portion 3C.
When the blade 3 rotates, the fluid passing to the string direction passes through the large bulged front face 3D at a high speed according to the Coanda effect. The fluid passing through the front face 3D is faster than the velocity of the fluid passing through the back face 3E without bulge, and for the fluid that the flow velocity is faster than the surroundings, its density becomes lower density and the pressure drops lower than the ambient.
A fluid of normal pressure flows into the fluid of reduced pressure from the surroundings, as a result, the fluid pressure increases and the fluid moves to the direction of the blade tip portion, then, the fluid gathers at the inclined portion 3C and strikes it, as a result, the fluid passes through the bulged front face 3D in the inclined portion 3C to the direction of the rear edge portion 3G of the string, the propulsive force is generated as a reaction.
In FIG. 5, the fluid that passes through the front face 3D to the direction of the rear edge portion 3G flows to the direction of the arrow D, but since the back face 3E has almost no angle of attack with respect to the rotation direction, in the portion close to the maximum string length, the fluid flowing along the back face 3E, that is, the fluid pushed by the blade generates the propulsive force.
In FIG. 6, fluid flowing to the direction of the rear edge portion 3G along the string direction of the front face 3D flows into the direction of the arrow C. The fluid pushed out by the back face 3E is pushed out to the direction of the arrow c, but the amount is not the ratio of the amount of water along the front face 3D.
In FIG. 7, fluid flowing along the front face 3D of the maximum string length portion 3B flows into the direction of the arrow B at a high speed. The arrow B direction is opened in a direction away from an axial line S of the rotor 1, as compared with the arrow C direction in FIG. 6. This has the action of rotating the blade 3 to the rotation direction as a reaction.
FIG. 8 shows a cross section of the inclined portion 3C. In FIG. 8, the inclined portion 3C is inclined to the front direction (rotor shaft direction) of the front face 3D. As shown in FIG. 8, since the front face 3D has a large bulge, due to the rotation, the fluid passing at high speed according to the Coanda effect from the rear edge portion 3G to the back face 3E direction along the string direction at the front face 3D of the inclined portion 3C passes to the direction of the arrow A, the propulsive force is generated as a reaction.
Since the amount of the fluid in a certain period of time gathered in the maximum string length portion 3B is a fluid which gathers from the direction of the blade root portion 3A by centrifugal force and other fluid pressure change due to the rotation, as a quite large reaction, that is, the rotational speed of the rotor 1 is increased, and a large propulsive force is generated to the direction of the rotor shaft 4.
As being apparent from FIGS. 4 to 8, when this rotor 1 is used as a propulsion machine under water of a ship, since this rotor 1 does not push out water with the blade 3 like a conventional screw, an action of pushing out water by force against the resistance of water does not occur.
That is, as shown in FIG. 2, in the blade 3, since the thickness of the blade tip portion is thinner than the blade root portion 3A, the rotational resistance does not become large. When the blade 3 rotates, since a rotating circumferential speed at the blade root portion 3A is small, even if the front edge portion 3F is thick, it hardly becomes resistant.
At the blade tip portion with a high rotating circumferential speed, since the front edge portion 3F and the rear edge portion 3G are pointed and the thickness gradually increases toward the middle of the front face 3D like the half meat of a fish, the relative flow with respect to the front edge portion 3F during rotation passes at high speed according to the Coanda effect and the resistance does not occur when it passes through the largest thickness portion of the front face 3D to the string direction.
In this way, the rotor 1 does not push out water to the downstream direction by the blade 3, due to the rotation of the blade 3, the relative flow generated in the string direction becomes the high speed water flow according to the Coanda effect at the front face 3D, and passes from the rear edge portion 3G to the back face 3E direction, the propulsive force is generated as a reaction.
As a result, the blade 3 does not push out water by force, so that large power is not required. Since Coanda effect naturally occurring due to the rotation of the blade 3 is utilized, when the blade 3 rotates, the Coanda effect naturally occurs, and when the flow velocity of the fluid along the front face 3D is faster than the fluid along the back surface 3E, the high speed flow naturally passes to the direction of the back face 3E.
FIG. 9 shows the rotor 1 of the present invention mounted on the propulsion machine of a watercraft 5 above water, and FIG. 10 is a side view showing a partial cross section of a rotor housing 7. The rotor housing 7 is horizontally mounted on the back deck of the watercraft 5 via a support 6. A rotor shaft 10 connected to a motor 8 and a clutch 9 is supported in the rotor housing 7, and the rotor 1 is disposed at the tip of the rotor shaft 4.
The front end portion of the rotor shaft 4 is connected to the motor 8 via the clutch 9 so that the rotor 1 can be rotated by the motor 8, but when the clutch 9 is disconnected, the rotor 1 can be rotated by wind power. Number of blades 3 is arbitrarily set within the range of 2 to 6 sheets.
A rotation number of the rotor shaft 4 is measured by a measuring instrument 10 provided in the rotor housing 7, and the measured value is inputted to an automatic controller 11. When the motor 8 is started and the clutch 9 is connected, the rotor 1 is rotated by the motor 8.
Due to the rotation of the rotor 1, when the air current generated by the blade 3 is discharged in the directions indicated by arrows F and F in FIG. 9, the watercraft 5 gains the propulsive force and moves forwards.
That is, since the air current concentrates to the direction of the axial center in the direction of the back face 3E, the propulsive force becomes large.
When the rotational speed of the rotor 1 is increased, the propulsive force is further increased. As a result, by adding a small auxiliary motor, a strong propulsive force can be obtained. The rotor 1 may be used as a screw under water.

INDUSTRIAL APPLICABILITY

By rotating with a small power, a high speed flow caused according to the Coanda effect occurring in the string direction of the flow receiving surface of the blade passes from the rear edge portion to the back face direction, and the propulsive force can be obtained as a reaction, so that the rotor 1 is used as a propulsion machine such as a small watercraft.

Reference Signs List

1 horizontal shaft rotor
2 hub
3 lift-type blades
3A blade root portion
3B maximum string length portion
3C inclined portion
3D front face (upstream side)
3E back face (downstream side)
3F front edge portion
3G rear edge portion
4 rotor shaft
5 watercraft
6 support
7 rotor housing
8 motor
9 clutch
10 measuring instrument
11 automatic controller
A to F fluid flow direction
S rotating axial line

Claims

1. A horizontal shaft rotor comprising a lift-type blade, in the lift-type blade, a front face in a flow receiving direction is a large arcuate bulging face in a string direction, a rear face in a discharge direction is made smaller than the bulge of the front face, when the blade rotates, a high speed flow caused according to the Coanda effect passing along the string direction of the front face from a rear edge portion to a back face direction generates propulsive force.

2. The horizontal shaft rotor according to claim 1, wherein, in the lift type blade, the back face in the discharge direction at the blade root portion is linear in the string direction and parallel to the rotation direction, the back face is gradually increased inclination to a front face direction from the blade root portion to a maximum string length portion, and from the rear edge portion to a front edge portion.

3. The horizontal shaft rotor according to claim 1, wherein, in the lift-type blade, in a side view, a thickness gradually decreases from the blade root portion to a blade tip portion, and the front face gradually inclines to the back face direction from the blade root portion to the blade tip portion.

4. A watercraft comprising the horizontal shaft rotor according to claim 1, wherein the horizontal shaft rotor is mounted on a rotor shaft of a rotor housing disposed in the watercraft so that a tip of an inclined portion of a blade is oriented in a bow direction.

5. The horizontal shaft rotor according to claim 2, wherein, in the lift-type blade, in a side view, a thickness gradually decreases from the blade root portion to a blade tip portion, and the front face gradually inclines to the back face direction from the blade root portion to the blade tip portion.

6. A watercraft comprising the horizontal shaft rotor according to claim 2, wherein the horizontal shaft rotor is mounted on a rotor shaft of a rotor housing disposed in the watercraft so that a tip of an inclined portion of a blade is oriented in a bow direction.

7. A watercraft comprising the horizontal shaft rotor according to claim 3, wherein the horizontal shaft rotor is mounted on a rotor shaft of a rotor housing disposed in the watercraft so that a tip of an inclined portion of a blade is oriented in a bow direction.