Multi-Stage Transmission Using Nested Planetary Gears
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Increasing the number of gear shift stages in vehicle transmissions to improve fuel economy leads to increased parts, complexity, and weight, which complicates installation, raises costs, and reduces efficiency.
Innovation Solution
A multi-stage transmission design utilizing four planetary gear devices and six gear shift elements, including clutches and brakes, to achieve 9 forward and 1 reverse stages with a minimal number of parts and a straightforward structure, optimizing gear ratios for efficient engine operation and reduced noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the number of gear shift stages is increased to improve fuel economy, then the engine can operate at more efficient points and fuel economy is improved, but the number of parts increases, complexity increases, and weight increases
Solution Approach 1:
The patent merges multiple planetary gear devices into a single integrated transmission system where four planetary gear devices share common rotary elements and shafts. This consolidation achieves 9 forward stages and 1 reverse stage while using fewer independent components compared to traditional multi-stage transmissions, directly resolving the contradiction between achieving high gear stage count and maintaining low part complexity
Solution Approach 2:
The planetary gear devices are designed with multi-functional rotary elements that serve multiple purposes simultaneously. For example, the third rotary element of one planetary gear device serves as the second rotary element of the next planetary gear device, allowing single components to perform multiple gear ratio functions and eliminating the need for separate components for each stage
2Use of energy by moving object
If the number of gear shift stages is increased to improve fuel economy, then the engine can operate at more efficient points, but the cost of the transmission is increased
Solution Approach 1:
By consolidating four planetary gear devices into a single integrated unit with shared components, the patent reduces the total number of parts that need to be manufactured and assembled. This merging approach achieves 9 forward stages and 1 reverse stage while lowering manufacturing complexity and cost compared to traditional multi-stage transmissions that would require separate gear sets for each stage
3Use of energy by moving object
If the number of gear shift stages is increased to improve fuel economy, then the engine can operate at more efficient points, but the weight of the transmission is increased
Solution Approach 1:
The patent merges four planetary gear devices into a compact integrated structure where components are shared across multiple gear stages. This consolidation achieves 9 forward stages and 1 reverse stage while minimizing the total weight of the transmission system compared to traditional designs that would require separate, heavier components for each gear stage
Solution Approach 2:
The planetary gear devices are arranged in a nested configuration where rotary elements of one planetary gear device serve as input or output elements for adjacent planetary gear devices. This nesting approach compactly packs multiple gear stages into a smaller volume and reduces overall weight compared to distributed arrangements
4Object-affected harmful factors
If the number of gear shift stages is increased, then the engine can be driven within a relatively low RPM range and noise is attenuated, but the ease of fitting the transmission in the vehicle is lowered
Solution Approach 1:
The patent arranges four planetary gear devices in a nested configuration where rotary elements are shared between adjacent devices, creating a compact transmission structure. This nesting approach fits 9 forward stages and 1 reverse stage into a compact package that is easier to install in vehicle spaces compared to traditional multi-stage transmissions with distributed components
Solution Approach 2:
By merging multiple planetary gear devices into a single integrated unit with shared shafts and rotary elements, the patent creates a compact transmission assembly that occupies less space and is easier to fit into vehicle installations while achieving low RPM operation and noise reduction
5Speed
If the number of gear shift stages is increased, then the engine can be driven within a relatively low RPM range, but the transfer efficiency of the transmission is reduced
Solution Approach 1:
The patent merges four planetary gear devices into an integrated system with shared rotary elements, creating direct mechanical connections that minimize energy loss. This consolidation achieves 9 forward stages and 1 reverse stage with improved power transfer efficiency compared to traditional multi-stage transmissions that use more intermediate components and connection points where energy can be lost
Data Source
AI summary
A multi-stage transmission for vehicles includes an input shaft for receiving power from an engine; an output shaft for outputting the power; and a first, a second, a third, and a fourth planetary gear device. Each of the planetary gear devices has three rotary elements. The transmission further includes a first rotary shaft connected to the input shaft; a second rotary shaft; a third rotary shaft; a fourth rotary shaft; a fifth rotary shaft; a sixth rotary shaft; a seventh rotary shaft connected to a first rotary element of the third planetary gear device; and an eighth rotary shaft connected to a third rotary element of the fourth planetary gear device and to the output shaft.