Gearbox Transmission Layout With Nested Freewheel for Compact Shifting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing two-speed transmission systems for electric vehicles face issues with excessive mechanical stress and large footprint due to components rotating at high speeds, such as freewheels and multi-disc clutches, which are mounted on the input shaft, leading to compatibility problems with vehicle space constraints.
Innovation Solution
A transmission mechanism with a first shaft, a driven wheel, a switching mechanism, and a freewheel device, where the freewheel device is axially superposed by teeth of the switching mechanism, reducing the total axial length and mechanical stress, and incorporating a friction clutch positioned separately to minimize space and improve mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the freewheel and multi-disc clutch are mounted on the input shaft rotating at high speed, then the transmission system can achieve gear changing capability, but the mechanical stress and drag torque become excessive
Solution Approach 1:
The patent relocates the freewheel device from the high-speed input shaft to the low-speed output shaft, effectively changing the dimensional context from high-speed rotation to low-speed rotation. This dimensionality change in rotational speed allows the freewheel mechanism to operate under reduced mechanical stress and drag torque while maintaining its gear changing function through the interaction between the locking member and gear teeth.
Solution Approach 2:
The transmission system is segmented into two distinct functional zones: the input shaft handling power input and the output shaft handling gear changing operations. By separating the freewheel device from the high-speed input shaft and placing it on the low-speed output shaft, the system divides the functional responsibilities, allowing each component to operate in its optimal speed range and reducing overall mechanical stress.
2Area of stationary object
If multiple components are mounted on the same input shaft, then the transmission system can be compact in radial direction, but the axial footprint becomes significant
Solution Approach 1:
The patent redistributes components along the axial dimension rather than concentrating them on a single shaft. By moving the freewheel device to the output shaft and positioning it axially adjacent to other components, the system transforms the spatial arrangement from radial stacking to axial distribution, reducing the overall axial footprint while maintaining radial compactness.
Solution Approach 2:
The freewheel device is nested within the existing transmission structure by positioning it axially adjacent to the gear teeth and locking member. This nested arrangement allows the freewheel mechanism to occupy space that would otherwise be unused, achieving compact integration without significantly increasing the overall axial length of the transmission system.
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
The solution results in a compact, robust, and cost-effective transmission mechanism that allows gear changes without power interruption, with reduced mechanical stress and optimized space utilization.
Implementation Method 1
a friction clutch positioned separately to minimize space and improve mechanical strength
Data Source
AI summary
A transmission mechanism for a gearbox includes a first shaft, a first driven wheel rotatably guided on the first shaft, a switching mechanism and a freewheel device. The freewheel device includes a locking member rotatably interacting with the first shaft and with the first driven wheel. The first driven wheel includes first teeth that rotatably interact with second teeth of the switching mechanism in a first engaged position and do not rotatably interact with the second teeth in a second disengaged position. The first teeth and the second teeth at least partially axially cover the locking member in the first engaged position.