Work Vehicle Transmission Layout for Compact Multi-Stage Speed Change
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Solution Overview
Problem
Existing work vehicle speed changing arrangements using hydrostatic stepless speed changers and planetary gear speed changers are complex and prone to enlargement, with complications in suppressing corotation and cost increases due to increased components.
Innovation Solution
A work vehicle configuration featuring a hydrostatic stepless speed changer device and multiple planetary gear speed changer devices arranged in juxtaposition, with corresponding clutch mechanisms to take off driving power individually, all accommodated within a transmission case, allowing for compactness and simplification without compromising speed changing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple planetary gear speed changer devices are arranged in series to achieve multiple speed stages, then speed changing capability is improved, but device complexity and length increase
Solution Approach 1:
The patent transitions from arranging planetary gear speed changers in series (one-dimensional linear arrangement) to arranging them in parallel (utilizing two-dimensional spatial distribution). This dimensional change allows multiple speed changing sections to operate simultaneously without increasing the overall length of the transmission system, thereby maintaining speed changing capability while reducing device complexity and compacting the structure.
Solution Approach 2:
The patent divides the transmission system into multiple independent planetary gear speed changing sections that can be selectively engaged or disengaged. Each section can be independently controlled by its own clutch mechanism, allowing the system to achieve multiple speed stages by combining different sections rather than requiring a long series arrangement of all sections.
2Adaptability or versatility
If clutch mechanisms are arranged in series with planetary gear sections to take off driving power, then individual power takeoff capability is improved, but the overall arrangement lengthens
Solution Approach 1:
The patent arranges clutch mechanisms in parallel with their corresponding planetary gear sections rather than in series along the same axis. This allows multiple clutch mechanisms to be positioned at different radial locations, enabling individual power takeoff from each planetary section without extending the axial length of the transmission system.
Solution Approach 2:
The clutch mechanisms are designed as universal power takeoff devices that can be selectively engaged to connect or disconnect driving power from different planetary gear sections. This multi-functional design allows the same clutch mechanism type to serve multiple sections, achieving versatile power takeoff capability without requiring specialized components for each section.
3Reliability
If a corotation preventing arrangement with brake member and piston is added, then corotation suppression is improved, but device complexity and cost increase
Solution Approach 1:
The patent integrates the corotation preventing function directly into the existing clutch mechanisms and planetary gear sections. The clutch mechanisms serve dual purposes: both for power takeoff and for preventing corotation. By merging these functions into existing components rather than adding separate brake members and pistons, the system achieves reliable corotation suppression without increasing device complexity or component quantity.
Solution Approach 2:
The planetary gear sections and clutch mechanisms are designed to inherently prevent corotation through their own structural characteristics and operational principles. The system uses its existing components to suppress corotation without requiring external or additional dedicated anti-corotation devices, allowing the transmission system to serve its own reliability needs.
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 configuration effectively suppresses the disadvantageous enlargement of the speed changing arrangement, simplifies the system, and maintains the advantages of using hydrostatic stepless and planetary gear speed changers, while also preventing corotation and reducing costs.
Implementation Method 1
a hydrostatic stepless speed changer device configured to speed-change driving power of an engine steplessly
Implementation Method 2
a plurality of planetary gear speed changer devices configured to speed-change the driving power speed-changed by the stepless speed changer device
Data Source
Figure 1
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Figure 4
AI summary
A work vehicle includes a hydrostatic stepless speed changer device 20 configured to speed-change driving power of an engine 4 steplessly, a plurality of planetary gear speed changer devices Q1, Q2 configured to speed-change the driving power speed-changed by the stepless speed changer device 20, a plurality of clutch mechanisms C1, C2 corresponding to the plurality of planetary gear speed changer devices Q1, Q2 in order to take off the driving powers from these plurality of planetary gear speed changer devices Q1, Q2 individually, and a traveling speed changer device 50 for speed-changing and transmitting the driving powers transmitted from the plurality of clutch mechanisms C1, C2 to a traveling mechanism. The plurality of planetary gear speed changer devices Q1, Q2, the plurality of clutch mechanisms C1, C2, and the traveling speed changer device 50 are accommodated in a transmission case.