Driving Device Speed Ratio Setting for Construction Machines
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Solution Overview
Problem
Self-propelled construction machines face challenges in efficiently changing the speed of rotation of their working devices, leading to increased wear, fuel consumption, and safety hazards due to the need for time-consuming coupling processes and slip modes during speed synchronization.
Innovation Solution
A second drive train with a summation transmission connects the second driving unit to the working device, allowing for clutch-free starting, accelerating, and decelerating, and continuous adjustment of the working device's speed without affecting the first driving unit's optimal operating speed, using a planetary gear system that eliminates the need for torque converters and allows for variable speed control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the gear system operates in slip mode during coupling to synchronize speeds, then the working device can be connected, but wear increases and component lifespan shortens
Solution Approach 1:
The patent replaces the traditional mechanical slip-mode coupling system with an electrical coupling system. The electrical drive unit can synchronize speeds electronically without mechanical slipping, eliminating wear on mechanical components while maintaining the ability to connect and disconnect the working device. This substitution of electrical for mechanical coupling resolves the contradiction between ease of coupling operation and component durability.
2Ease of operation
If the main drive alternates between idling and operating speeds to enable coupling, then the working device can be connected, but fuel consumption increases
Solution Approach 1:
The patent segments the drive system into a main drive and a separate electrical drive unit. The electrical drive unit handles all coupling and speed adjustment operations independently, allowing the main drive to remain at constant optimal operating speed. This segmentation eliminates the need for the main drive to alternate between idle and operating speeds, thereby resolving the contradiction between operational ease and energy efficiency.
Solution Approach 2:
The electrical drive unit serves multiple functions: it enables coupling operations, adjusts working device speed, and maintains main drive operation at optimal speed. This multi-functional electrical system replaces the single main drive that previously had to perform both propulsion and coupling functions, resolving the contradiction by allowing the main drive to focus solely on efficient propulsion.
3Loss of time
If the milling rotor runs at operating speed during maneuvering mode to avoid time-consuming coupling, then coupling time is reduced, but uncontrolled acceleration risk increases if contact with ground occurs
Solution Approach 1:
The patent replaces mechanical coupling constraints with electrical control. The electrical drive unit can instantly adjust the milling rotor speed and provide controlled braking, eliminating the risk of uncontrolled acceleration even when the rotor runs at operating speed during maneuvering. This electrical control system resolves the contradiction by maintaining safety while reducing time loss.
4Adaptability or versatility
If a second driving unit is added to enable independent speed control, then speed adjustment flexibility improves, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical speed adjustment mechanisms with a simpler electrical drive unit. The electrical system provides flexible speed control through electronic regulation rather than mechanical gear changes or slip mechanisms. This substitution achieves high adaptability with reduced structural complexity, resolving the contradiction between speed adjustment flexibility and device 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 reduces energy consumption, minimizes wear on components, and simplifies the coupling process, enabling faster, safer, and more efficient operation of construction machines by allowing the working device to operate at optimal speeds without interrupting the first drive unit's operation.
Implementation Method 1
A second drive train comprising a second driving unit between the second driving unit and the working device and in that the two drive trains are connected via a summation transmission
Data Source
AI summary
The present invention relates to a device in a self-propelled construction machine with a first driving unit, which provides for a first speed of rotation (n1). By means of a planetary gear the first speed of rotation (n1) is translated into a different speed of rotation (n3) at which a working device of the construction machine, in particular a milling rotor for processing ground surfaces, can be operated.