Differential Drive Arrangement for Low-Inrush Variable Speed Startup
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing drive arrangements for working machines that require variably adjustable speed are complex and expensive, often leading to high inrush currents during startup, which can cause mains disturbances or overheating.
Innovation Solution
A drive arrangement comprising a differential gear, a first drive unit, a working machine, and a second drive unit, with an auxiliary gear stage and a switching element that automatically couples or decouples the speeds of the drive units based on the transmission ratio of the auxiliary gear stage, allowing for safe and efficient ramp-up to nominal speed without the need for a control unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-speed-adjustable drive unit is connected to the mains, then the working machine can be operated, but an excessively high inrush current is caused which can lead to mains disturbances or overheating
Solution Approach 1:
The auxiliary gear stage acts as an intermediary mechanical element between the drive unit and the working machine. During startup, it provides a temporary transmission path that allows the drive unit to be accelerated to operating speed through mechanical coupling rather than direct electrical connection, thereby eliminating inrush current while ensuring reliable startup
2Adaptability or versatility
If electric motors with variable-frequency drive are used to drive a working machine at variably adjustable speed, then the speed can be adjusted, but the system becomes complex and expensive
Solution Approach 1:
The patent replaces complex electrical control systems (variable-frequency drives) with a purely mechanical solution consisting of a differential gear and auxiliary gear stage. This mechanical substitution achieves variable speed adjustment through gear ratio changes while eliminating the need for complex electronic control equipment, thereby reducing system complexity and cost
3Adaptability or versatility
If a gearbox with hydraulically or electrically driven superimposed branch is used for variable transmission ratio, then the transmission ratio can be adjusted, but the system becomes complex and expensive
Solution Approach 1:
The transmission system is segmented into two independent but coupled parts: a main differential gear for primary speed adjustment and an auxiliary gear stage for additional ratio modification. This segmentation allows each gear stage to be simpler in design while their combined effect provides the required variable transmission ratio, reducing overall complexity compared to a single complex gearbox
Data Source
AI summary
A drive arrangement of a working machine includes a differential gear, a first drive unit coupled to a first element of the differential gear, a working machine coupled to a second element of the differential gear, and a second drive unit coupled to a third element of the differential gear. The speed of the second drive unit can be superimposed on a speed that is dependent on the speed of the first drive unit, whereby the first or second drive unit can be driven at a variably adjustable speed. When a switching element is closed, an auxiliary gear stage is load-transmitting and speeds of the first and second drive units are coupled as a function of at least one transmission ratio of the auxiliary gear stage, and when the switching element is open, the auxiliary gear stage is load-free and speeds of the first and second drive units are decoupled.