Work Vehicle Transmission Single-Clutch Shift Segmentation

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Solution Overview

Problem

Multi-swap shifts in powershift transmissions for work vehicles often result in poorer shiftability, leading to reduced comfort and efficiency due to larger gear ratio changes and the need for simultaneous clutch swaps in multiple stages, which can be costly and inefficient.

Innovation Solution

A transmission system with a configuration of multiple shafts, clutches, and gear pairs that allows for single-clutch swaps between adjacent gear ratios, enhancing shiftability by using a larger number of ratios with smaller steps, thereby improving comfort and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multi-swap shifts are used to achieve larger number of speeds economically, then the number of speeds increases, but shiftability deteriorates due to simultaneous clutch swaps in multiple stages

Engineering Contradiction:
Improvenumber of speedsVSAvoidshiftability
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The transmission is divided into multiple stages with separate clutch control for each stage. Each stage has its own clutch that can be independently controlled, allowing single-swap shifts within each stage rather than requiring simultaneous multi-stage clutch swaps. This segmentation enables economical achievement of multiple speeds while maintaining smooth single-swap shifting characteristics.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If multi-swap shifts with larger gear ratio changes are used, then the number of speeds increases, but comfort and efficiency are reduced

Engineering Contradiction:
Improvenumber of speedsVSAvoidefficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

By dividing the transmission into multiple stages with smaller individual gear ratio steps, the overall system achieves a large number of speeds while each individual shift involves only small ratio changes. This segmentation allows the transmission to provide both high adaptability (many speeds) and high productivity (efficient operation with small ratio steps).

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the gear ratio parameters within each stage to be smaller and more closely spaced, rather than using large ratio steps. This parameter change enables smooth, efficient single-swap shifts while still achieving a large overall range of speeds through the combination of multiple stages.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3279511B1Transmission system for a work vehicle
Publication Date: 2020.05.13 CNH IND ITALIA SPA
  • EP3279511B1 patent drawingFigure 1
  • EP3279511B1 patent drawingFigure 2
  • EP3279511B1 patent drawingFigure 3~4

AI summary

A transmission system for a work vehicle includes a transmission. The transmission includes a first shaft, a second shaft, an input shaft, an output shaft, and an input gear pair comprising a first input gear and a second input gear. The transmission includes a first input clutch configured to selectively couple the input shaft to the first shaft, and a second input clutch configured to selectively couple the input shaft to the second shaft via the input gear pair. The transmission includes an output gear pair comprising a first output gear and a second output gear, wherein the first output gear is coupled to the first shaft, or the second output gear is coupled to the output shaft. The transmission also includes a first output clutch configured to selectively couple the second output gear to the output shaft, and a second output clutch configured to selectively couple the second shaft to the output shaft. The transmission further includes a first module, wherein the first module includes a first module clutch and a first module gear pair having a first module gear and a second module gear, wherein the first module gear is coupled to the first shaft and the first module clutch is configured to selectively couple the second module gear to the second shaft, or the second module gear is coupled to the second shaft and the first module clutch is configured to selectively couple the first module gear to the first shaft.