Snowmobile Upper Arm Geometry Reducing Frame Force
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional snowmobile designs experience increased force on the vehicle frame through the upper arm due to the position of the lower arm, which also leads to increased running resistance in deep snow as it gets hit by snow, causing inefficiency.
Innovation Solution
The snowmobile design positions the upper arm higher than conventional designs, with the lower arm positioned higher than the rotational center of the crank shaft and secondary shaft, reducing the force on the vehicle frame and minimizing snow impact by positioning the lower arm to avoid deep snow contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the lower arm is positioned low to reduce force on the vehicle frame, then the force on the vehicle frame is reduced, but the lower arm hits snow in deep snow causing increased running resistance
Solution Approach 1:
The patent changes the vertical position parameter of the lower arm from a low position to a high position (above the rotational center of the crankshaft). This parameter change simultaneously achieves two objectives: it reduces the force on the vehicle frame through the upper arm by altering the lever arm geometry, and it prevents snow impact on the lower arm by raising it above the snow contact zone in deep snow conditions.
2Force
If the upper arm is positioned higher, then the force on the vehicle frame is reduced, but the center of gravity may be affected
Solution Approach 1:
The patent employs asymmetric positioning where the lower arm is specifically positioned above the rotational center of the crankshaft while the upper arm extends outwardly to connect to the knuckle. This asymmetric arrangement optimizes the force distribution and lever arm geometry to reduce force on the vehicle frame, while the overall vehicle design maintains balance to prevent excessive center of gravity elevation.
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
This configuration reduces the force on the vehicle frame and decreases running resistance in deep snow without raising the center of gravity, enhancing efficiency and performance.
Implementation Method 1
an upper arm including a proximal portion connected to the ski support frame and extending outwardly in the vehicle width direction from the proximal portion to connect to the knuckle, the proximal portion being rotatable so that the ski and the knuckle can move up and down relative to the ski support frame
Implementation Method 2
When the ski moves up and down, a force acting on the ski from the snow surface is transmitted to the vehicle frame via the knuckle and the upper arm. At this time, the knuckle works like a lever, and the connecting point between the knuckle and the lower arm works as the fulcrum of the lever.
Implementation Method 3
a drive system including an engine and a secondary shaft, the engine being disposed rearward of the ski support frame and including a crank shaft, the secondary shaft being located higher than the crank shaft and configured to receive a drive force from the crank shaft
Data Source
AI summary
The present specification relates to a snowmobile. The upper arm includes two proximal portions connected to the vehicle frame and the upper arm extends outwardly from the two proximal portions in the vehicle width direction and the upper arm is connected to the knuckle. The two proximal portions are rotatable so that the knuckle and the skis can move up and down relative to the vehicle frame. The axis Ax2, passing through the rotation center C2 of the two proximal portions of the upper arm, goes through a position of the rotation center of the secondary shaft or through a position above the rotation center of the secondary shaft. This structure can reduce the force acting on the vehicle body frame via the upper arm and prevent an increase in the force.