Compact Gearbox With Compound Planet Gears
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Solution Overview
Problem
Conventional gearboxes are overly complex and bulky, making them unsuitable for applications requiring compactness and multiple gear options, especially with the advent of electrical motors that can operate at various speeds and directions.
Innovation Solution
The design incorporates a compound planet gear assembly with two ring gears and a shifting mechanism that allows for different gear selections by engaging either the first or second ring gear with the shifting mechanism, changing the rotational speed ratio of the shafts, and utilizing hydraulic actuation to eliminate the need for seals and reduce complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional gearbox designs are used to provide multiple gears, then gear options are available, but the gearbox becomes complex and bulky
Solution Approach 1:
The gearbox is segmented into modular components: a compound planet gear assembly with multiple planet gear sets, separate ring gears for different gear selections, and an independent shifting mechanism. This segmentation allows each component to perform specific functions, reducing overall complexity while providing multiple gear options.
Solution Approach 2:
The compound planet gear assembly employs nested gearing where multiple planet gear sets are arranged concentrically around a sun gear, with each planet gear set engaging with different ring gears. This nesting arrangement provides multiple gear ratios within a compact space, avoiding the need for separate gear trains for each selection.
2Adaptability or versatility
If conventional gearbox designs are used to provide multiple gears, then gear options are available, but the gearbox size increases
Solution Approach 1:
Multiple planet gear sets are nested concentrically within a single compact assembly, with each set capable of engaging different ring gears. This nesting provides multiple gear ratios without requiring separate gear trains, significantly reducing the volume needed for multiple gears.
Solution Approach 2:
The patent utilizes the radial dimension by arranging multiple planet gear sets at different radii around the sun gear, allowing each set to engage with ring gears of different diameters. This dimensional arrangement provides multiple gear options within a compact footprint, avoiding linear expansion of gearbox volume.
3Device complexity
If hydraulic actuation is used for shifting, then seals are eliminated and complexity is reduced, but the shifting mechanism must handle high pressure
Solution Approach 1:
A hydraulic shifting mechanism uses fluid pressure to engage and disengage ring gears with the planet gear assembly. The hydraulic actuation eliminates the need for mechanical seals and complex linkage mechanisms, reducing overall gearbox complexity while providing reliable gear selection. The hydraulic system is designed to operate at pressures sufficient to overcome gear engagement forces.
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 approach results in a compact gearbox capable of handling high torques and speeds, reducing the need for a clutch and providing flexible gear options without the complexity of traditional designs, suitable for applications like electric vehicles.
Implementation Method 1
utilizing hydraulic actuation to simplify the gearbox structure
Data Source
AI summary
Provided are gearboxes including compound planet gear assemblies as well as methods of using such gearboxes. A gearbox includes at least a first ring gear and a second ring gear. Depending on the current gear selection, one of these ring gears may be engaged with a shifting mechanism or not engaged with any ring gears when in a neutral gear. The first ring gear may be constantly engaged with a first planet gear of a compound planet gear assembly, while the second ring gear may be constantly engaged with a second planet gear of the same compound planet gear assembly. The first planet gear may be also engaged with a sun gear coupled to a shaft. Another shaft is coupled to the shifting mechanism. Different gear selections of the gearbox engage different ring gears to the shifting mechanism thereby changing the rotational speed ratio of the two shafts.