Hydrostatic Manual Transmission Gear Shift Retry Control
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Solution Overview
Problem
In transmission arrangements with a hydrostatic transmission and a manual transmission connected downstream, the safe engagement of gears cannot be guaranteed due to temperature fluctuations and manufacturing tolerances, leading to potential shift failures and increased operator burden.
Innovation Solution
A method where the system automatically detects unsuccessful gear engagements, re-engages the original gear, and retries the gear change within a permissible shift window, with the electronic control unit managing the hydrostatic and manual transmissions to adjust the hydraulic motor speed and synchronize gear changes without operator intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the hydrostatic motor speed is adjusted slightly above the exact speed for gear engagement, then the gear engagement process is simplified and driving comfort is improved, but the safe engagement of the gear cannot be guaranteed due to temperature fluctuations and manufacturing tolerances
Solution Approach 1:
The patent implements a feedback mechanism by detecting whether the gear engagement was successful after the shifting process. If the detected gear stage does not match the desired gear stage, the system automatically triggers a retry sequence to re-engage the original gear and attempt the shift again, thereby ensuring reliable gear engagement despite initial failures caused by temperature fluctuations or manufacturing tolerances.
Solution Approach 2:
The transmission arrangement performs self-correction by automatically detecting failed gear engagements and re-attempting the shift without operator intervention. The electronic control unit autonomously manages the retry process, including re-engaging the original gear and adjusting the hydrostatic motor speed, thereby eliminating the need for manual monitoring and correction by the operator.
2Device complexity
If no detection measures are provided for gear engagement status, then the transmission arrangement structure is simpler, but the operator burden increases as they must manually monitor correct gear engagement
Solution Approach 1:
The patent incorporates detection devices that provide feedback on the actual gear stage to the electronic control unit. This feedback mechanism automatically informs the system whether a gear engagement was successful, eliminating the need for the operator to manually monitor gear engagement status while maintaining relatively simple system architecture.
Solution Approach 2:
The transmission arrangement performs self-monitoring and self-correction by automatically detecting failed gear engagements and re-attempting the shift without operator intervention. This self-service capability significantly reduces the operator's workload while maintaining straightforward system design.
3Loss of time
If the gear change is attempted immediately without retrying the original gear, then the shifting process is faster, but tension in the transmission prevents successful engagement of the desired gear
Solution Approach 1:
The patent applies preliminary action by automatically re-engaging the original gear before attempting the desired gear shift again. This preparatory step relieves transmission tension that may have built up during the failed engagement attempt, creating favorable conditions for successful gear engagement on the retry while minimizing additional time loss.
Solution Approach 2:
The system implements periodic retry attempts with a predetermined delay between attempts. This periodic action allows the transmission to settle and tension to be relieved between shift attempts, improving the likelihood of successful engagement while maintaining efficient operation through automated retry sequences.
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
This method ensures reliable gear engagement by overcoming tension issues and reducing operator workload, while preventing excessive speed jumps and wear on the transmission, ensuring smooth gear changes and improved driving comfort.
Implementation Method 1
a hydrostatic transmission (3) and a manual transmission (4) connected downstream, in particular for travel drives
Implementation Method 2
when they are changed using a synchronizing device, the speed of the hydraulic motor of the hydrostatic transmission is adapted to the respective driving situation and thus to the rotational speed of the transmission input shaft of the downstream manual transmission
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a method for changing gear stages (10, 11) in a transmission having a hydrostatic transmission (3) and a downstream manual transmission (4), and a corresponding transmission arrangement. First, a desire to shift is detected within the manual transmission (4) to change the gear stages. The hydrostatic transmission (3) and the downstream manual transmission (4) are activated to change the gear stage (10, 11) of the downstream transmission (4). Whether the gear stage (10, 11) to be engaged through a gear stage change was successfully engaged is detected by means of a detection device (17, 18), which is connected to an electronic control unit (15) of the transmission arrangement. If the engagement of the gear stage (10, 11) to be engaged is not successful, the original gear stage (10, 11) is reengaged. After the engagement of the original gear stage (10, 11), the downstream transmission (4) is again activated such that the gear stage (10, 11) to be engaged is engaged.