Powershift Transmission Segmentation for Crawler Gear Mode
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Solution Overview
Problem
Conventional powershift transmissions are complex to produce and do not allow for additional operating modes like crawler gear mode, with inefficiencies in shifting times and performance due to their design.
Innovation Solution
A powershift transmission design where the first output shaft is connected to the output-side sun gear with a first shifting element and directly to the input shaft with a second shifting element, allowing for three interchangeable gear sets and eliminating the need for a ring gear, resulting in a compact, easy-to-manufacture, and efficient structure with improved shifting performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional two-stage powershift transmission with planetary gear is used, then the transmission can operate in through-drive mode or reduction mode, but the production technology becomes complex and additional operating modes like crawler gear mode cannot be achieved
Solution Approach 1:
The transmission system is segmented into two independent single-stage planetary gear sets (first planetary gear set and second planetary gear set) instead of one two-stage planetary gear set. Each planetary gear set can be independently controlled by its own clutch, allowing flexible combination of operating modes while simplifying the overall structural complexity
Solution Approach 2:
Each planetary gear set is designed to provide multiple operating modes (through-drive, reduction, reversing, and crawler gear modes) through independent clutch control. The first planetary gear set can operate in through-drive mode when its clutch is engaged, and the second planetary gear set can provide reduction, reversing, and crawler gear modes when its clutch is engaged, making each gear set universal and multi-functional
2Ease of manufacture
If a two-stage planetary gear set is used, then through-drive and reduction modes are achieved, but the structure is complex and manufacturing costs increase
Solution Approach 1:
The complex two-stage planetary gear set is divided into two simpler single-stage planetary gear sets. This segmentation reduces the complexity of each individual gear set, making them easier to manufacture while maintaining the overall functional capabilities through independent clutch control
Solution Approach 2:
The invention extracts and eliminates the need for a ring gear component from the conventional two-stage planetary gear set design. By using two independent single-stage planetary gear sets with sun gears and planet gears controlled by clutches, the complex ring gear structure is removed, simplifying manufacturing and reducing costs
3Loss of time
If a conventional planetary gear design with ring gear is used, then gear ratios are achieved, but the mass inertia increases and shifting times are prolonged
Solution Approach 1:
The ring gear component is completely removed from the planetary gear sets. By using only sun gears and planet gears in two independent single-stage planetary gear sets, the design eliminates the heavy ring gear structure, reducing mass inertia and enabling faster shifting times while maintaining all required operating modes through clutch control
Data Source
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AI summary
The invention relates to a power shift transmission (10). The power shift transmission comprises an input shaft (18), a first output shaft (20) arranged coaxially to the input shaft (18), a planetary transmission (22) having a planet carrier (28), which is connected to the input shaft (18), and at least one stepped planetary set (30), the stepped planetary set (30) engaging on the input side and the output side with a sun gear (52, 44) in each case, and at least two shift elements (24, 26). To produce a variable power shift transmission for several pairings of various operation modes, the first output shaft (20) can be connected to the output-side sun (44) of the stepped planet set (30) by means of a first shift element (24) and the first output shaft (20) can be directly connected to the input shaft (18) by means of a second shift element (26), the input-side sun gear (52) of the stepped planetary set (30) being non-rotatably connected to a housing part (12) of the power shift transmission (10).