Snowmobile Ski Keel and Pivot Axis Geometry for Steering Load Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Snowmobiles equipped with four-stroke engines face challenges in reducing steering load while maintaining improved straight travel and cornering characteristics, as four-stroke engines are heavier, increasing the force required for steering and complicating the enhancement of both performance metrics.
Innovation Solution
The design incorporates a steering mechanism with a power steering device, a pair of skis with specific pivot axes configurations, and keel portions to enhance straight travel and cornering without increasing steering load, allowing the skis to pivot effectively and maintain contact with the snow surface, supported by a connecting section that allows horizontal and vertical pivotal movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a four-stroke engine is used, then exhaust gas cleanliness is improved, but steering load increases due to increased engine weight
Solution Approach 1:
A power steering device is introduced as an intermediary mechanism between the rider and the steering system. This device provides assisted steering force to counteract the increased steering load caused by the heavier four-stroke engine, allowing the rider to operate the steering mechanism with reduced effort while maintaining the environmental benefits of the four-stroke engine
2Stability of the object's composition
If the straight portion of the ski is extended rearward to improve straight travel, then straight travel characteristic is improved, but cornering characteristic deteriorates
Solution Approach 1:
The invention resolves the contradiction by introducing a new dimensional parameter - the longitudinal position relationship between the first pivot axis and the second pivot axis. By positioning the first pivot axis forward of the second pivot axis, the ski geometry creates distinct functional zones: the extended rearward straight portion ensures stable straight travel by maintaining contact area behind the second pivot axis, while the forward position of the first pivot axis enables effective cornering by allowing the ski to pivot about a forward point during turning operations
3Ease of operation
If the first pivot axis is positioned forward to improve cornering, then cornering characteristic is improved, but straight travel characteristic may deteriorate
Solution Approach 1:
The invention applies local quality by creating different functional characteristics at different portions of the ski. The forward position of the first pivot axis optimizes the forward portion for cornering responsiveness, while the extended rearward straight portion optimizes the rearward portion for straight travel stability. This localized functional differentiation allows both cornering and straight travel characteristics to be improved simultaneously
Data Source
AI summary
A snowmobile includes a body, a steering mechanism provided in the body, a steering shaft connected with the steering mechanism for associated operation with the steering mechanism, a power steering device provided in the steering shaft, a pair of skis, and a connecting section arranged to connect the skis with the body. Each of the skis includes, in its lower surface, a straight portion extending straightly; an approach portion ahead of the straight portion and curving upward; and a keel portion protruding downward to a lower position than the straight portion and the approach portion.