Underwater propulsive device of watercraft

Patent metadata

Field	Value
Publication number	US-11097822-B2
Application number	US-201816485394-A
Country	US
Kind code	B2
Filing date	Feb 8, 2018
Priority date	Feb 13, 2017
Publication date	Aug 24, 2021
Grant date	Aug 24, 2021

Abstract

An underwater propulsive device of a watercraft including a flotation unit on which a user rides. The propulsion device includes: a hollow body coupled to the flotation unit through a strut and extending in a propulsive direction of the watercraft, the inside of the hollow body being divided into a first compartment and a second compartment; a motor in the first compartment; a propeller in the second compartment; and a power transfer shaft extending in the propulsive direction and connecting the motor and the propeller to each other. The first compartment has a waterproof structure. The second compartment has a water inlet disposed closer to the bow than the propeller is and extending along a circumference of the power transfer shaft and a water jet outlet disposed at a stern-side end of the second compartment. The propeller is smaller than the first compartment in diameter.

First claim

The invention claimed is:

1. An underwater propulsive device configured to be driven underwater, the underwater propulsive device comprising:
a hollow body provided with a first compartment in which a motor is housed and provided with a second compartment including a water passage; and
a cooling water passage configured to cool the motor, at least a portion of the cooling water passage housed within the first compartment, the cooling water passage including a discharge port in fluid communication with the water passage of the second compartment.

2. The underwater propulsive device according to claim 1 , further comprising:
a motor driving circuit housed in the first compartment; and
wherein the cooling water passage is configured to cool the motor driving circuit.

3. The underwater propulsive device according to claim 2 , wherein:
the second compartment is configured to house a propeller;
the cooling water passage of the second compartment has a water inlet and a water jet outlet; and
the discharge port of the cooling water passage is configured to communicate with the water inlet.

4. The underwater propulsive device according to claim 3 , wherein the water inlet is covered with a filter configured to prevent foreign matter from entering into the second compartment.

5. The underwater propulsive device according to claim 1 , wherein the first compartment has a waterproof structure.

6. The underwater propulsive device according to claim 1 , further comprising a motor driving circuit housed in the first compartment and interposed between the motor and a bow side of the hollow body.

7. The underwater propulsive device according to claim 1 , wherein:
the second compartment is interposed between the first compartment and a stern side of the hollow body;
the second compartment includes a water inlet and a propeller; and
the cooling water passage includes a suction port in fluid communication with the discharge port.

8. The underwater propulsive device according to claim 2 , wherein the motor driving circuit corresponds to an inverter.

9. An underwater propulsive device of a watercraft including a flotation unit on which a user rides, the underwater propulsive device comprising:
a hollow body coupled to the flotation unit via a strut; and
a hydrofoil coupled to the hollow body, and
wherein the hydrofoil is configured to move based on a distance between the flotation unit and a water surface.

10. The underwater propulsive device according to claim 9 , wherein the hydrofoil is configured to maintain a predetermined distance between the flotation unit and the water surface.

11. The underwater propulsive device according to claim 9 , wherein the hydrofoil is configured to move upward and downward.

12. The underwater propulsive device according to claim 9 , wherein the hydrofoil is coupled to a bow side of the hollow body.

13. The underwater propulsive device according to claim 9 , wherein the hydrofoil is configured to reduce tilts of the watercraft in a bow direction and a stern direction during traveling of the watercraft.

14. The underwater propulsive device according to claim 9 , wherein the hydrofoil is detachably attached to the hollow body.

15. The underwater propulsive device according to claim 9 , wherein bow hydrofoil is attached to a bow side of the hollow body.

16. The underwater propulsive device according to claim 15 , wherein the hydrofoil is detachably attached to the hollow body.

17. The underwater propulsive device according to claim 15 , wherein the bow hydrofoil is configured to generate upward force by traveling of the watercraft.

18. The underwater propulsive device according to claim 17 , wherein the hydrofoil is detachably attached to the hollow body.

19. The underwater propulsive device according to claim 9 , wherein:
the underwater propulsive device is provided with a water surface sensor configured to measure a distance between the flotation unit and the water surface;
the water surface sensor includes a bar and a contact plate; and
a front end of the bar is attached to the strut so to be rotatable upward and downward, and the contact plate is attached to a rear end of the bar.

20. The underwater propulsive device according to claim 9 , further comprising a cooling water passage configured to cool a motor housed within a first compartment of the hollow body, at least a portion of the cooling water passage housed within the first compartment.

Assignees

• Yanmar Co Ltd
• Yanmar Power Technology Co Ltd

Inventors

• Aoki Hideaki
• Ouchida Takeshi

Classifications

• B63B34/50

  Body-supporting buoyant devices, e.g. bathing boats or water cycles (swimming aids A63B31/00) · CPC title

• B63H11/08 Primary

  of rotary type · CPC title

• B63H2011/081

  with axial flow, i.e. the axis of rotation being parallel to the flow direction · CPC title

• B63B32/60 Primary

  Board appendages, e.g. fins, hydrofoils or centre boards · CPC title

• B63B32/10

  Motor-propelled water sports boards (power-driven personal watercraft B63B34/10) · CPC title