Shiftable Earth-Working Transmission for Uniform Gear Wear
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Solution Overview
Problem
Earth working machines with shiftable transmissions experience uneven wear in gear pairs due to different operating conditions, leading to increased maintenance needs and inefficient power transfer, as they typically step down power in rotation speed and up in torque, causing load-dependent losses and suboptimal operation.
Innovation Solution
The design incorporates a shiftable transmission with a direct drive mode that connects the input and output shafts directly, allowing for uniform wear of components and reduced load-dependent losses, along with a secondary gearing stage that modifies rotation speed and torque, enabling operation at optimal steady-state rotation speed with varying torque and rotation speed combinations without overloading specific components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a shiftable transmission with multiple gearing stages having different torque transfer ratios is used, then the drive motor can operate at optimal steady-state rotation speed, but uneven wear occurs in gear pairs due to different operating conditions
Solution Approach 1:
The transmission is divided into two independent gearing stages (first and second gear pairs), each with its own intermediate shaft and clutch. This segmentation allows independent operation and wear distribution across stages, preventing concentrated wear in a single gear pair while maintaining efficient drive motor operation.
2Power
If torque transfer is stepped down in rotation speed and stepped up in torque, then power transfer capability is improved, but load-dependent losses increase
Solution Approach 1:
The transmission dynamically switches between two different torque transfer ratios using shiftable clutches. This allows the system to adapt to varying load conditions, selecting the appropriate gearing stage to minimize load-dependent losses while maintaining adequate torque transfer capability.
3Adaptability or versatility
If intermediate shafts with shiftable clutches are used to enable torque transfer path shifting, then adaptability between different gearing stages is improved, but device complexity increases
Solution Approach 1:
The shiftable clutch mechanism is extracted as a separate, modular component on each intermediate shaft. This allows the complexity to be managed through standardized, replaceable units rather than integrated complex mechanisms, facilitating maintenance and reducing overall system complexity.
4Reliability
If only one intermediate clutch can be in torque-transferring state at any given moment, then reliability through load path clarity is improved, but productivity during shifting operations decreases
Solution Approach 1:
The transmission is designed to maintain continuous torque transfer capability during shifting operations. By having two independent gearing stages with separate clutches, the system can transition between stages without complete interruption of power flow, maintaining productivity while ensuring reliable torque transfer paths.
Data Source
AI summary
An earth working machine (10), encompassing a drive motor (42) and a working apparatus (22) drivable by the drive motor (42) so as to move rotationally, the drive motor (42) being connected to the working apparatus (22), for transfer of a torque, with interposition of a shiftable transmission (50; 150) comprising at least two gearing stages having different torque transfer ratios,is characterized in that by means of a first gearing stage of the shiftable transmission (50), an input shaft (48), coupled on the input side to the drive motor (42), of the shiftable transmission (50) is connectable in torque-transferring fashion directly to an output shaft (52), coupled on the output side to the working apparatus (22), of the shiftable transmission (50) so as to rotate together at the same rotation speed; and by means of a second gearing stage of the shiftable transmission (50), the input shaft (48) is connectable in torque-transferring fashion, with interposition of a transmission assemblage (64), to the output shaft (52) so as to rotate together at different rotation speeds.