Watercraft steering system, and watercraft

• US 8,162,706 B2
• Filed: 11/19/2007
• Issued: 04/24/2012
• Est. Priority Date: 11/17/2006
• Status: Expired due to Fees

• Current Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Original Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Inventors: Mizutani, Makoto, Uchiyama, Ryuji
• Primary Examiner(s): Vasudeva, Ajay
• Application Number:
  US11/942,187
• Publication Number:
  US 20080119094A1
• Time in Patent Office: 1,618 Days
• Field of Search: 114/144.R, 114/150, 114/144.RE, 114/144.E, 440/1, 440/53, 440 58- 60, 440/61.R, 440 61 S- 61 C, 440/62, 440/63
• US Class Current: 440/53
• CPC Class Codes: B63H 20/12 Means enabling steering
• CPC Class Codes: B63H 25/02 Initiating means for steering , for slowing down, otherwise than by use of propulsive elements, or for dynamic anchoring
• CPC Class Codes: B63H 25/20 by mechanical means
• CPC Class Codes: B63H 25/24 by electrical means
• CPC Class Codes: B63H 25/42 Steering or dynamic anchoring by propulsive elements by jets B63H25/46; Steering or dynamic anchoring by propellers used therefor only; Steering or dynamic anchoring by rudders carrying propellers

Abstract

A watercraft can have an electric motor mounted on a screw bar extending in a right/left direction. The electric motor can move along the screw bar in the right/left direction to steer an outboard motor, or another part of a different marine propulsion system. One or more springs can be provided at the ends of the screw bar. When the outboard motor whose steered angle exists in a predetermined angle range including the maximum steered angle is steered back to a neutral position, either one of the springs presses the electric motor toward the center of the screw bar to assist the steering torque of the electric motor.

Claims

1. A steering system for a watercraft arranged to pivot a watercraft propulsion unit laterally relative to a hull of the watercraft, to move the propulsion unit from a neutral position in right and left directions by a driving force of a steering actuator, the steering system comprising:

a steering assist device to generate a predetermined urging force in a direction toward the neutral position when the watercraft propulsion unit is steered toward at least one of the right direction and the left direction relative to the neutral position;

wherein

the steering assist device applies the urging force to the steering actuator in the direction toward the neutral position when a steered angle of the watercraft propulsion unit is in a predetermined angle range including a maximum steered angle and does not apply any urging force to the steering actuator when the steered angle of the watercraft propulsion unit is in the neutral position and when the steered angle of the watercraft propulsion unit is outside of the predetermined angle range; and

the steering system further comprises a shaft whose axial direction is arranged along the right and left directions of the watercraft hull, the steering actuator is disposed movably along the axial direction of the shaft, and wherein the steering assist device comprises an urging device disposed at end portions of the shaft to press the steering actuator in the direction toward the neutral position.

2. The watercraft steering system according to claim 1, wherein the steering assist device applies the urging force in an opposite direction relative to a direction in which a propeller rotation reaction force is generated when the watercraft propulsion unit is driven.

3. The watercraft steering system according to claim 1, wherein the urging device comprises at least one of a cylinder and piston combination, a coil spring and a torsion spring.

4. The watercraft steering system according to claim 1, wherein the steering actuator is an electrically operable actuator.

5. The watercraft steering system according to claim 1 in combination with a watercraft propulsion unit according mounted to a watercraft.

6. The watercraft steering system according to claim 5, wherein the watercraft propulsion unit is an outboard motor.

7. A steering system for a watercraft arranged to pivot a watercraft propulsion unit laterally relative to a hull of the watercraft from a neutral position in right and left directions with a steering actuator, the steering system comprising:

a left steering assist device and a right steering assist device configured to generate a predetermined force in a direction toward the neutral position when the watercraft propulsion unit is steered toward the right direction and the left direction relative to the neutral position;

wherein

the left steering assist device or the right steering assist device is configured to apply the predetermined force to the steering actuator in the direction toward the neutral position when a steered angle of the watercraft propulsion unit is in a predetermined angle range including a maximum steered angle and each of the left steering assist device and the right steering assist device is configured not to apply any force to the steering actuator when the steered angle of the watercraft propulsion system is in the neutral position and when the steered angle of the watercraft propulsion system is outside of the predetermined angle range; and

the steering system further comprises a shaft whose axial direction is arranged along the right and left directions of the watercraft hull, the steering actuator is disposed movably along the axial direction of the shaft, and wherein each of the left steering assist device and the right steering assist device comprises an urging device disposed at end portions of the shaft and configured to press the steering actuator in the direction toward the neutral position.

8. The watercraft steering system according to claim 7, wherein one of the left steering assist device and the right steering assist device is configured to apply a force larger than the predetermined force in an opposite direction relative to a direction in which propeller rotation reaction force is generated when the watercraft propulsion unit is driven.

9. The watercraft steering system according to claim 7, wherein the urging device comprises at least one of a cylinder and piston combination, a coil spring, and a torsion spring.

10. The watercraft steering system according to claim 7, wherein the steering actuator is an electrically operable actuator.

11. The watercraft steering system according to claim 7 in combination with a watercraft propulsion unit according mounted to a watercraft.

12. The watercraft steering system according to claim 11, wherein the watercraft propulsion unit is an outboard motor.