Single Shaft Two-Speed Drive System Reducing Noise and Vibration
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Solution Overview
Problem
Conventional electric vehicle drive systems face challenges with increased volume and weight due to separate shafts for the gear box and differential, leading to decreased fuel efficiency and increased noise and vibration, and are limited in achieving suitable gear reduction ratios.
Innovation Solution
A single-shaft two-speed drive system utilizing a synchronizer and two planetary gear sets to achieve gear reduction along the same axial line, allowing for active gear reduction and power generation on a single drive shaft, reducing noise and vibration, and increasing fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the gear box and differential are disposed on separate shafts, then the power transmission can be achieved, but the volume and weight are increased
Solution Approach 1:
The patent combines the gear box and differential onto a single shaft, merging two previously separate components into one integrated power transmission system. This consolidation reduces the overall volume and weight while maintaining the necessary power transmission functionality through shared structural support and aligned rotational axes.
Solution Approach 2:
The single shaft serves multiple functions simultaneously: it acts as both the gear box shaft and the differential shaft, supporting both components and transmitting power through both mechanisms. This multi-functional design eliminates the need for separate shafts, reducing system complexity, volume, and weight.
2Ease of manufacture
If the gear box is disposed outside the housing, then the installation space is available, but the overall volume and weight are increased
Solution Approach 1:
The gear box is nested within the housing structure, with the gear box shaft and differential shaft integrated into the same housing space. This nesting arrangement allows the gear box to be installed within the available housing volume rather than requiring external space, thereby reducing the overall vehicle packaging volume while maintaining manufacturability.
3Productivity
If multiple shafts are used for power transmission, then the gear reduction can be achieved, but the fuel efficiency is decreased
Solution Approach 1:
By merging the gear box and differential onto a single shaft, the patent reduces the number of mechanical connections and power transmission paths. This reduction in transmission stages minimizes energy losses through friction and mechanical inefficiencies, thereby improving fuel efficiency while maintaining the required gear reduction capability through the integrated component design.
4Volume of stationary object
If the planetary gear set is used, then the compact design is achieved, but the gear reduction ratio is passively limited
Solution Approach 1:
The patent introduces a synchronizer mechanism that dynamically adjusts the gear reduction ratio by controlling the engagement and disengagement of planetary gear sets. This dynamic control system allows the gear ratio to be actively changed based on driving conditions, transforming the previously passive, fixed ratio limitation into an adaptable, multi-ratio system while maintaining the compact planetary gear architecture.
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 system effectively reduces noise and vibration, increases fuel efficiency, and provides a broader range of gear reduction ratios by densely disposing the motor, two planetary gear sets, and differential within a single housing, while actively managing gear reduction.
Implementation Method 1
a first planetary gear set including: a first sun gear configured to be rotated in conjunction with the rotor, and configured such that a plurality of gear teeth are formed on an outer circumferential surface thereof; a plurality of first planetary gears configured to engage with gear teeth of the first sun gear and be operated in conjunction with the first sun gear; a first ring gear configured such that an internal gear adapted to engage with the first planetary gears is formed on an inner circumferential surface
Implementation Method 2
A single-shaft two-speed drive system utilizing a synchronizer and two planetary gear sets to achieve gear reduction along the same axial line, allowing for active gear reduction and power generation on a single drive shaft
Data Source
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AI summary
Disclosed herein is a single-shaft two-speed drive system including a synchronizer. The single-shaft two-speed drive system includes: a housing; a motor unit including a stator and a rotor; a first planetary gear set including a first sun gear, a plurality of first planetary gears, a first ring gear, and a first carrier; a second planetary gear set including a fastening cone, an integrating cone, a synchronizer, a second sun gear, a plurality of second planetary gears, a second ring gear, and a second carrier; and a differential; wherein the sleeve is moved in a direction of the fastening cone and coupled to the fastening cone to thus obtain a single gear reduction ratio and the sleeve is moved in a direction of the integrating cone and coupled to the integrating cone to thus obtain driving power without gear reduction.