Outboard Motor Tilt Shaft Layout for Greater Trim-In Angle

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Solution Overview

Problem

Conventional outboard motors with internal combustion engines face limitations in trim-in due to lubricating oil combustion issues and interference with the hull, while those with electric motors struggle to achieve significant trim-in without interfering with the hull, limiting their posture control and propulsion efficiency.

Innovation Solution

The outboard motor design incorporates an electric motor with a tilt shaft positioned closer to the lower end of the stern, allowing for a greater trim-in angle by minimizing interference with the hull, and includes a lift mechanism for enhanced tilt-up, enabling angles up to 30° or more without interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If the tilt shaft is positioned in the vicinity of the upper portion of the outboard motor main body to enable great tilt-up, then the upper portion can be lifted out of water effectively, but the lower portion moves forward by a large amount during trim-in and interferes with the hull

Engineering Contradiction:
Improvetilt-up capabilityVSAvoidinterference with hull during trim-in
Core Design Contradiction:
Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent repositions the tilt shaft from a horizontal arrangement to a vertical arrangement, changing the dimension of rotation. This allows the outboard motor main body to rotate about a vertical axis, enabling independent control of tilt-up and trim-in movements without the coupling effects present in conventional horizontal tilt shaft designs.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent separates the tilt-up and trim-in functions into independent rotational movements about different axes. The tilt shaft enables tilt-up rotation about a vertical axis, while the trim mechanism independently controls trim-in, allowing each function to be optimized without compromising the other.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If the outboard motor main body is trimmed in to a great extent to improve posture control, then the degree of freedom in posture control increases, but lubricating oil is burned in the fuel chamber causing white smoke

Engineering Contradiction:
Improveposture control capabilityVSAvoidwhite smoke from lubricating oil combustion
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the reciprocating internal combustion engine with an electric motor, eliminating the mechanical combustion process that causes lubricating oil to burn and produce white smoke. This substitution allows unlimited trim-in capability without the harmful effects of oil combustion.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If the tilt shaft is positioned closer to the lower end of the stern to reduce forward movement of the lower portion during trim-in, then the amount of trim-in can be increased, but the upper portion may interfere with the hull during tilt-up

Engineering Contradiction:
Improvetrim-in angleVSAvoidinterference with hull during tilt-up
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

By changing the tilt shaft orientation to vertical, the patent decouples the horizontal and vertical movements, allowing the lower portion to move forward during trim-in without restricting the upper portion's ability to move upward during tilt-up. The vertical rotation axis allows independent control of both movements.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4242097B1Outboard motor capable of being tilted up and trimmed in, and marine vessel therewith
Publication Date: 2026.05.06 YAMAHA MOTOR CO LTD
  • EP4242097B1 patent drawingFigure 1
  • EP4242097B1 patent drawingFigure 2
  • EP4242097B1 patent drawingFigure 3A~3C

AI summary

An outboard motor includes a main body with a power source therein and a bracket to be attached to a stern of a hull. The main body rotates about a rotating shaft of the bracket, such that an upper portion of the main body moves toward the front of a marine vessel and a lower portion of the main body moves toward the rear of the marine vessel, or such that the upper portion of the main body moves toward the rear of the marine vessel and the lower portion of the main body moves toward the front of the marine vessel. In the hull on sailing, the distance from the rotating shaft to the upper end of the stern is equal to or longer than the distance from the rotating shaft to a propeller shaft, with respect to the vertical direction of the marine vessel.