Tractor PTO Gearbox Shifting Under Load Without Powershift
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Solution Overview
Problem
Agricultural machines, such as tractors, face challenges in shifting transmission gear stages during the operation of attached implements, especially during start-up processes, due to the lack of powershiftability and high loads on the clutch, which can lead to clutch failure.
Innovation Solution
A control device is implemented to switch transmission gear stages in the PTO shaft transmission by controlling the drive motor or braking device, allowing synchronization without additional mechanical components, enabling gear shifting during the drive and start-up processes, even in architectures that typically do not allow shifting under load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional PTO transmission without powershift capability is used, then the structure is simple, but gear shifting during operation is not possible and clutch loads are extremely high
Solution Approach 1:
The patent replaces traditional mechanical synchronization devices with a control device that electronically controls the clutch and gear shifting mechanism. The control device receives synchronization signals and coordinates clutch engagement/disengagement with gear stage transitions, eliminating the need for complex mechanical synchronizers while enabling seamless shifting under load
Solution Approach 2:
The control device serves multiple functions: it manages clutch engagement, coordinates gear stage transitions, and ensures synchronization during shifting operations. This multi-functional approach consolidates what would traditionally require separate mechanical components into a single electronic control system
2Reliability
If starting implement with high moment of inertia in low gear ratio is used, then the implement can be started, but repeated start-up attempts place enormous loads on the clutch leading to failure
Solution Approach 1:
The patent enables dynamic gear ratio adjustment during the start-up process. The control device can transition between gear stages based on operational conditions, allowing the system to adapt to high-load start-up scenarios without overloading the clutch. This dynamic shifting capability distributes the mechanical stress across multiple gear stages rather than concentrating it in a single low gear ratio
3Ease of operation
If PTO transmission with mechanical synchronization device is used, then shifting under load is possible, but the transmission requires large space and many mechanical components
Solution Approach 1:
The patent replaces traditional mechanical synchronization devices with a control device that electronically controls the clutch and gear shifting mechanism. The control device receives synchronization signals and coordinates clutch engagement/disengagement with gear stage transitions, eliminating the need for complex mechanical synchronizers while enabling seamless shifting under load
Solution Approach 2:
The patent extracts the synchronization function from the mechanical transmission components and relocates it to an electronic control system. This separation allows the mechanical components to remain simple while the electronic control device handles the complex synchronization logic, reducing overall mechanical complexity
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 solution allows for more powerful and efficient start-up processes of implements with high flywheel weights and reduces clutch stress, enabling automatic switching and extended service life of the PTO shaft transmission components.
Implementation Method 1
a braking device (25) operatively connected to the transmission input shaft (12) and the PTO (13)
Data Source
Figure 1
Figure 2
AI summary
The present invention relates to an agricultural machine (1), in particular a tractor (2), with a drive motor (5) and a power take-off (PTO) gearbox (10), which are connected to each other by means of a clutch (11). The PTO gearbox (10) comprises a gearbox input shaft (12) and a power take-off shaft (13) for driving an implement (3, 4) that can be attached to the agricultural machine (1), wherein the gearbox input shaft (12) can be connected to the PTO shaft (13) via a first gearbox gear stage (22) or a second gearbox gear stage (23). The PTO gearbox (10) further comprises a shifting device (24) and a braking device (25).The agricultural machine (1) is characterized in that it comprises a control device (28) which is designed to selectively control either the drive motor (5) or the brake device (25) during the operation of an implement (3, 4) attached to the agricultural machine (1) for a shifting operation from the first gear stage (22) to the second gear stage (23) depending on a PTO speed.