Eccentric L-Shaped Shift Rod for Outboard Motor Durability
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Solution Overview
Problem
Existing outboard motor designs face challenges in improving durability while avoiding increases in size and weight, particularly when the distance between shift rod axes is limited, leading to unnecessary enlargement of the motor's external shape.
Innovation Solution
The design incorporates a shift rod system with a first rod and a second rod, where the second rod is disposed eccentrically with respect to the first rod, connected by a joint, allowing for a reliable distance creation between the second rod and the drive shaft without substantial structural changes, thus enhancing durability and preventing size increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the size of gears, bearings, and other components that transmit driving force is increased to reduce the load on each component, then the durability of the drive system is improved, but the distance between the drive shaft and the shift rod must be increased, which requires changing the position of the shift rod
Solution Approach 1:
The shift rod is configured in an L-shape rather than a straight line, changing its spatial arrangement from a single-dimensional linear path to a two-dimensional angular configuration. This allows the shift rod to accommodate increased component sizes and greater distance between the drive shaft and shift rod position without requiring substantial changes to the overall motor structure, thereby improving durability while maintaining compact dimensions.
Solution Approach 2:
The shift rod is divided into two segments: a first rod extending in the vertical direction and a second rod extending in the front-back direction and disposed eccentrically. This segmentation allows each segment to be optimized independently - the first rod maintains vertical alignment while the second rod provides the necessary horizontal offset, enabling the shift rod to achieve both structural stability and proper spacing for durable component design.
2Reliability
If the position of the shift rod is changed to accommodate larger components, then the durability is improved, but substantial changes in the overall structure of the outboard motor must be made, resulting in increases in weight and external size
Solution Approach 1:
By configuring the shift rod in an L-shape with vertical and horizontal segments rather than repositioning it entirely, the design achieves necessary spacing for durable components without requiring substantial structural changes to the motor housing or mounting structures, thereby avoiding unnecessary weight increases.
Solution Approach 2:
The shift rod employs an asymmetric L-shaped configuration with a vertical first rod and a horizontally extending second rod that is eccentrically disposed. This asymmetric design optimizes the spatial arrangement to provide necessary clearance for larger components while maintaining a compact overall structure, avoiding the weight penalty that would result from symmetric or fully repositioned configurations.
3Ease of operation
If gears are fixed to each of the lower shift rod and the upper shift rod to transmit rotation, then the shift mechanism functions, but a distance is needed to dispose the gears between the two shift rods, which cannot be used when the distance between the axes of the two shift rods is equal to or less than the diameter of each rod
Solution Approach 1:
The invention removes the gears from the shift rod transmission mechanism entirely, extracting this intermediate transmission element. The shift rod directly operates the shifter through its L-shaped configuration and eccentric disposition, eliminating the need for gears and the distance space they would require between upper and lower shift rods.
Solution Approach 2:
The L-shaped shift rod configuration with its vertical first rod and eccentric horizontal second rod serves as a geometric intermediary that directly transmits motion from the shifter to the gear mechanism without requiring intermediate gears. This mediator structure provides the necessary motion transformation and spacing without the additional distance requirements of gear-based transmission.
4Ease of operation
If the distance between the axes of the two shift rods is increased to enable gear transmission, then the gear mechanism can function, but the external shape of the outboard motor becomes unnecessarily large
Solution Approach 1:
By removing the gears from the transmission path and using the L-shaped shift rod with eccentric disposition to directly operate the shifter, the invention eliminates the need for increased distance between shift rod axes, thereby preventing unnecessary enlargement of the motor's external shape.
Solution Approach 2:
The L-shaped shift rod configuration utilizes vertical and horizontal dimensions efficiently, with the first rod extending vertically and the second rod extending horizontally in an eccentric arrangement. This dimensional optimization allows the mechanism to function with minimal overall footprint, preventing unnecessary increases in the motor's external dimensions.
Data Source
AI summary
An outboard motor includes a shift rod including a first rod, a second rod, and a joint. The first rod extends in a vertical direction. The second rod extends in the vertical direction and is located below the first rod. The second rod is disposed eccentrically with respect to the first rod. When viewed in a plan view, the second rod overlaps with at least a portion of the first rod or is in contact with the first rod. The joint connects the first rod to the second rod.