Snowmobile Gearbox with CVT and Reverse Drive Mechanism
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Solution Overview
Problem
Snowmobiles lack advanced control over speed and torque, particularly in reverse operations, as many do not have a reverse function for their engines, limiting user maneuverability and versatility.
Innovation Solution
A snowmobile design incorporating a continuously variable transmission (CVT) connected to a gearbox with configurable gear pairings and a reverse drive mechanism, allowing users to select high, low, and neutral gears, as well as reverse operation through a shifter and actuator system, enabling greater control over speed and torque in both forward and reverse directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a CVT is used for speed and torque control, then transmission ratio variability is improved, but the degree of control over speed and torque remains insufficient
Solution Approach 1:
The patent combines a CVT with a gearbox having multiple fixed gear ratios (including reverse gear) into a single integrated transmission system. The CVT provides continuous variable ratio control while the gearbox provides discrete gear selections, creating a hybrid system that offers both continuous adjustability and fixed ratio options for enhanced control versatility.
Solution Approach 2:
The transmission system is designed to perform multiple functions: forward motion with variable ratios via CVT, forward motion with fixed ratios via gearbox, and reverse motion via the reverse gear pairing. This multi-functional design allows a single system to replace what would traditionally require separate transmission components.
2Adaptability or versatility
If reverse function is added to the transmission system, then maneuverability in reverse is improved, but device complexity increases
Solution Approach 1:
The reverse gear functionality is integrated into the gearbox structure by adding a reverse drive gear that meshes with the forward drive gear through an idler gear mechanism. This combines reverse capability with the existing forward gear system rather than requiring a completely separate reverse transmission system.
Solution Approach 2:
An idler gear is introduced as an intermediary component between the forward drive gear and the reverse driven gear. This idler gear enables reverse motion by reversing the direction of rotation without requiring complex clutching or braking mechanisms, simplifying the overall reverse function implementation.
3Measurement precision
If multiple gear pairings are provided for high and low gears, then control precision over speed and torque is improved, but the number of transmission components increases
Solution Approach 1:
The transmission system is segmented into distinct gear pairings (high gear and low gear) with specific ratio ranges for each. The CVT is divided into different operational ranges that correspond to these gear pairings, allowing optimized control precision for different speed and torque requirements without requiring a single complex mechanism.
Solution Approach 2:
The system dynamically switches between different gear pairings based on operating conditions. The CVT ratio range is adjusted according to the selected gear pairing, providing optimal control precision for each operational mode while maintaining flexibility to transition between modes as needed.
Data Source
AI summary
A snowmobile has a gearbox having a first shaft, a second shaft, first transmission gears mounted to the first shaft and second transmission gears mounted to the second shaft. A driven gear mounted to the first shaft engages a forward drive gear mounted to a countershaft. In a first configuration: the first shaft is coupled to the countershaft; when rotating, a driveshaft rotates in a same direction as the countershaft; and configurable portions of the countershaft and second shaft are free of gears. In a second configuration: the forward drive gear is in selective free-spin engagement with the countershaft; a reverse drive gear mounted to the configurable portion of the countershaft is in driving engagement with the countershaft; an actuator selectively transmits rotary motion from the countershaft to the gearbox; a reverse driven gear mounted to the configurable portion of the second shaft meshes with the reverse drive gear.