Outboard Motor Height Adjusting Unit Screw Mechanism
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Solution Overview
Problem
Existing outboard motors face challenges in accurately adjusting the propeller height without altering the trim angle, leading to increased traveling resistance and affected performance.
Innovation Solution
An outboard motor design featuring a height adjusting unit with a first member rotatably supported around the drive shaft axis, a second member fixed to the case, and a screw mechanism that converts rotational motion into vertical up and down motion, allowing precise adjustment of the propeller height without changing the trim angle, and a regulating portion to secure the adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a shaft adjuster with retaining holes is used to adjust height position, then the structure is simple and easy to manufacture, but the height position cannot be finely adjusted
Solution Approach 1:
The patent replaces the traditional mechanical retaining hole system with a screw mechanism. The screw thread converts rotational motion into precise linear displacement, enabling fine height adjustment without requiring multiple retaining holes. This substitution maintains structural simplicity while dramatically improving adjustment precision.
Solution Approach 2:
The invention changes the adjustment parameter from discrete stepwise positions (retaining holes) to continuous variable positioning through screw rotation. By varying the rotation angle of the screw, the height position can be adjusted to any desired value within the adjustment range, achieving high precision without increasing overall device complexity.
2Manufacturing precision
If trim angle is changed to adjust propeller height, then the height position can be adjusted, but the traveling resistance increases and performance is affected
Solution Approach 1:
The patent segments the adjustment function into two independent parts: trim angle adjustment and height position adjustment. The height adjusting unit operates independently on the propeller shaft assembly, allowing height adjustment without changing the trim angle. This segmentation eliminates the harmful effect of increased traveling resistance while achieving the desired height adjustment.
Solution Approach 2:
The invention introduces a dynamic height adjustment mechanism that operates independently of the static trim angle setting. The screw mechanism allows the propeller height to be dynamically adjusted while maintaining a constant trim angle, thereby avoiding the increase in traveling resistance that would result from trim angle changes.
3Measurement precision
If stepwise height adjustment is used, then the adjustment mechanism is simple, but the accuracy of propeller height from water surface cannot be adjusted with high accuracy
Solution Approach 1:
The patent substitutes the stepwise mechanical retaining hole system with a continuous screw mechanism. The screw thread provides a direct relationship between rotation angle and linear displacement, enabling precise height adjustment. This maintains ease of operation through simple rotational motion while achieving high measurement precision in propeller height adjustment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables high-accuracy adjustment of the propeller height, reducing traveling resistance and improving performance by allowing fine-tuned adjustments and secure fixation of the propeller position.
Implementation Method 1
a screw mechanism that converts rotational motion into vertical up and down motion
Data Source
AI summary
The outboard motor includes a drive shaft 4 that extends in a vertical direction, a propeller shaft that is connected to the drive shaft 4 to intersect the drive shaft 4, an upper case 2 that accommodates the drive source, a lower case 8 that accommodates the propeller shaft, and a height adjusting unit 9 that adjusts a height position between the upper case 2 and the lower case 8. The height adjusting unit 9 includes a first member 41 that is disposed coaxially with an axis C of the drive shaft 4, a second member 42 that is fixed to the lower case 8 and is screwed to the first screw portion 48, a rotation device 43 that rotates the first member 41, and a regulating portion 44 that restricts relative rotation between the first member 41 and the second member 42.