Electric Snowmobile Transmission Layout for Torque-Space Balance
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Solution Overview
Problem
Electric snowmobiles face challenges in packaging a suitable electric motor, drive sprocket, and battery pack within the limited space of a straddle seat vehicle while achieving both high torque and maximum speed, which are typically easier for combustion engine vehicles due to their design and continuously variable transmissions.
Innovation Solution
The design incorporates specific ratios for the rotor-to-sprocket, stator-to-sprocket, and transmission ratios, along with a strategically positioned battery pack that overlaps the electric motor and transmission, to optimize the conversion of rotational input into appropriate torque and speed for the drive track, allowing for a high-efficiency electric motor with a larger rotor and sprocket within the constrained space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a larger electric motor with bigger rotor and sprocket is used to achieve high torque, then torque performance is improved, but the vehicle packaging space is exceeded
Solution Approach 1:
The battery pack is positioned to overlap with the electric motor and transmission components in the longitudinal direction, creating a nested arrangement where components occupy overlapping spatial volumes. This allows the motor and battery to share space rather than requiring separate dedicated volumes, enabling larger motor components while maintaining compact overall vehicle packaging.
Solution Approach 2:
The design transitions from thinking about component placement in two dimensions (width and length) to utilizing the third dimension (height/vertical stacking) and longitudinal overlap. By allowing components to overlap in the longitudinal direction rather than placing them side-by-side, the design achieves larger motor components without increasing the overall vehicle footprint.
2Power
If a larger electric motor is used to achieve maximum speed and high torque, then performance is improved, but the device complexity increases
Solution Approach 1:
The design optimizes specific dimensional parameters of the motor and transmission system, including the rotor-to-sprocket diameter ratio (0.65-1.30), stator-to-sprocket length ratio (0.20-0.58), and rotor-to-transmission ratio (52-180 mm). By carefully selecting these parameters within defined ranges, the system achieves high performance while maintaining manageable complexity through standardized design relationships.
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 enables electric snowmobiles to achieve desired torque and speed performance comparable to combustion engine vehicles, providing an improved riding experience with extended high-speed and high-torque capabilities in off-road environments.
Implementation Method 1
an electric motor mounted to the frame; and a transmission mounted to the frame, the transmission drivingly engaging the electric motor to the drive track
Implementation Method 2
a drive track assembly having a drive track for engaging a ground and a sprocket rollingly engaged to the frame and meshed with the drive track
Data Source
AI summary
An electric snowmobile, has: a frame; a drive track assembly having a drive track and a sprocket; an electric motor mounted to the frame; and a transmission mounted to the frame, the transmission drivingly engaging the electric motor to the drive track, the transmission having an input drivingly engaged by the electric motor and an output drivingly engaging the sprocket, the transmission having a speed ratio defined as a rotational speed of the input to a rotational speed of the output, and wherein one or more of: a rotor-to-sprocket ratio ranging from 0.65 to 1.30, a rotor-to-transmission ratio ranging from 52 mm to 180 mm, a stator-to-sprocket ratio ranging from 0.20 to 0.58, and a rotor size-to-sprocket ratio ranging from 25 mm to 105 mm.