Planetary Gear Support Shaft Layout for Compact Bearing Packaging
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Solution Overview
Problem
Conventional planetary gear apparatuses for power transmission in hybrid electric vehicles face inefficiencies in weight, space, and assemblability due to large radial bearing sizes and complex supporting structures, which hinder fuel efficiency and environmental compliance.
Innovation Solution
A redesigned planetary gear apparatus with a sun gear spline-engaged to a first shaft, planet carriers supported by dedicated shafts, and a ring gear supported by bearings through these shafts, reducing radial bearing size and enhancing assemblability by forming a compact assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional planetary gear apparatus uses large radial bearings to support the ring gear, then the supporting structure is stable, but the radial bearing size increases leading to increased weight and reduced space efficiency
Solution Approach 1:
The patent divides the ring gear support function into two separate support shafts instead of using a single large bearing. Each support shaft carries its own bearing, splitting the load and allowing for more compact bearing selections while maintaining overall structural stability. This segmentation resolves the contradiction by achieving reliable support without requiring oversized individual bearings.
2Reliability
If conventional planetary gear apparatus uses complex supporting structures to ensure stability, then the gear set is reliable, but the device complexity increases hindering assembly and installation
Solution Approach 1:
The patent combines the support shafts with the ring gear structure itself, where the support shafts are integrated into the ring gear assembly. This merging reduces the number of separate components and simplifies the overall supporting structure while maintaining reliability through proper load distribution across the gear elements.
Solution Approach 2:
The support shafts serve multiple functions: they support the ring gear bearings, provide mounting points for the gear set, and act as structural elements of the overall assembly. This multi-functionality reduces the need for separate dedicated support components, thereby reducing device complexity while ensuring reliable operation.
3Reliability
If conventional planetary gear apparatus uses large radial bearings, then the supporting structure is stable, but the radial direction size increases reducing space efficiency
Solution Approach 1:
By segmenting the support system into two separate support shafts with individual bearings, the patent reduces the radial footprint compared to a single large bearing. Each bearing can be smaller in radial dimension while collectively providing the same or better support stability, thus resolving the contradiction between stability and compact radial size.
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
The solution improves space efficiency, reduces weight, and simplifies assembly and installation, leading to enhanced fuel efficiency and environmental compliance by optimizing the supporting structure of the planetary gear apparatus.
Implementation Method 1
an internal circumference of the sun gear is spline-engaged with an external circumference of the first shaft
Implementation Method 2
a first bearing interposed between the first support shaft and the supporting frame
Implementation Method 3
a second bearing interposed between the second support shaft and the transmission housing
Implementation Method 4
a third bearing interposed between the first planet carrier and the first support shaft
Implementation Method 5
a fourth bearing provided between an internal circumference of the second support shaft and an external circumference of the second shaft
Implementation Method 6
a plurality of pinion gears externally gear-engaged with the sun gear S, and a ring gear internally gear-engaged with the plurality of pinion gears P
Data Source
AI summary
A planetary gear apparatus for a power transmission apparatus including a transmission housing includes a sun gear provided on a first shaft, first and second planet carriers rotatably supporting pinion gears gear-engaged with the sun gear, and a ring gear gear-engaged with the pinion gears, where an internal circumference of the sun gear is spline-engaged with an external circumference of the first shaft, where first and second support shafts are fixed to first and second side surfaces of the ring gear, respectively, where the first support shaft is rotatably supported by a supporting frame fixed to the transmission housing, interposing a first bearing, where the second support shaft is rotatably supported by the transmission housing, interposing a second bearing, where the first planet carrier is rotatably supported by the first support shaft interposing a third bearing, and where the second planet carrier is fixedly connected to a connection end portion of a second shaft.