Shift Sleeve Transmission for Variable Harvester Speed
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Solution Overview
Problem
Existing transmission devices for agricultural harvesting machines are complex and expensive, often requiring multiple pulleys and complex designs to achieve variable rotational speeds, which can lead to component damage and premature wear due to high rotational speeds.
Innovation Solution
A transmission device with a shift sleeve configured as a hollow shaft, allowing axial displacement into multiple positions, featuring toothing pairings with a tooth pitch twice that of standard gear moduli, and utilizing detent bolts for secure positioning, enabling simplified shift operations and reduced torque during transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple pulleys and complex transmission devices are used to achieve variable rotational speeds, then the rotational speed control is improved, but the device complexity and cost increase
Solution Approach 1:
The transmission device is segmented into modular components: a shift sleeve with multiple toothing pairings, each pairing corresponding to a specific input shaft and speed ratio. This segmentation allows independent design and manufacturing of each toothing pairing, simplifying the overall complex system while enabling multiple speed variations through selective engagement of different pairings
Solution Approach 2:
The shift sleeve serves multiple functions simultaneously: it acts as a selector for different input shafts, provides multiple toothing pairings for different speed ratios, and includes detent mechanisms for positioning. This multi-functionality reduces the need for separate components, thereby reducing device complexity while maintaining rotational speed variation capability
2Manufacturing precision
If standardized toothed gear moduli are used, then the manufacturing precision is improved, but the tooth spacing is insufficient for reduced mechanical stress
Solution Approach 1:
The tooth pitch parameter is changed from standardized values to custom values that are larger than standard moduli. This parameter change increases the tooth spacing, which reduces mechanical stress and wear on the gear teeth during operation, while still maintaining manufacturing precision through controlled fabrication of the custom pitch dimensions
3Productivity
If high rotational speeds are used to increase productivity, then the output is improved, but component damage and premature wear increase
Solution Approach 1:
The design preliminarily counteracts the harmful effects of high rotational speeds by incorporating multiple toothing pairings with larger tooth spacing. This preliminary anti-action reduces mechanical stress and wear before damage can occur, allowing the system to operate at higher speeds for increased productivity while maintaining component durability and reliability
Data Source
AI summary
A transmission device and an agricultural harvesting machine include a first drive input element, a second drive input element, a shift sleeve configured as a hollow shaft, and a drive output shaft. The shift sleeve is mounted axially displaceably on the drive output shaft and is configured to be moved by axial displacement into one of a first position, a second position, and a third shift position. An internal toothing is formed on each of the first drive input element and the second drive input element. An external toothing and an internal toothing are formed on the shift sleeve. An external toothing is formed on the drive output shaft.