Planetary Gear Assembly With Hub-Ring Engagement for Low Noise
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Solution Overview
Problem
Conventional planetary gear assemblies suffer from noise issues and wear due to gaps between outer and inward-facing teeth, and manufacturing difficulties, especially in assembling the wheel hub with a spur gear.
Innovation Solution
A planetary gear assembly design featuring a wheel hub with engaging recesses and a second ring gear with joining protrusions that complement the recesses, allowing for smooth engagement and reduced wear, along with inclined surfaces for easy assembly and manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If gaps are formed between outer teeth and inward-facing teeth to facilitate assembly, then assembly is easier, but noise increases and wear occurs during operation
Solution Approach 1:
The wheel hub is segmented into multiple components: the hub body, sun gear, planet gears, first ring gear, and second ring gear. This segmentation allows each component to be manufactured and assembled separately, with the engaging recesses and joining protrusions enabling precise alignment without requiring pre-formed gaps between teeth.
Solution Approach 2:
The second ring gear acts as an intermediary component between the planet gears and the wheel hub. It features joining protrusions that engage with engaging recesses in the wheel hub, providing a stable connection that eliminates the need for gaps between outer teeth and inward-facing teeth, thereby reducing noise and wear while maintaining ease of assembly.
2Ease of operation
If outer teeth and inward-facing teeth are manufactured with gaps for assembly, then assembly is facilitated, but manufacturing precision is reduced
Solution Approach 1:
The engaging recesses are pre-formed in the wheel hub (or second ring gear) during manufacturing, and the joining protrusions are pre-formed on the second ring gear (or wheel hub). This preliminary action ensures precise alignment and engagement before final assembly, eliminating the need for post-assembly gap adjustment and maintaining high manufacturing precision.
3Ease of manufacture
If a wheel hub with a spur gear disposed thereon is manufactured, then gear function is achieved, but manufacturing difficulty increases
Solution Approach 1:
The sun gear is merged with the wheel hub by disposing the sun gear on the wheel hub and securing it in position. This merging eliminates the need for separate complex manufacturing processes for integrating the spur gear with the wheel hub, simplifying the overall manufacturing process while maintaining the gear function.
Data Source
AI summary
A planetary gear assembly includes a wheel hub surrounding an axis, and having an end face and a plurality of engaging recesses formed in the end face, and a planetary gear reduce mechanism including a sun gear disposed on and rotatable about the axis, a plurality of planet gears, and first and second ring gears. The planet gears angularly surround the sun gear and mesh with the sun gear and the first and second ring gears. The first ring gear is stationary relative to the planet gears. The second ring gear is arranged between the wheel hub and the first ring gear along the axis. The second ring gear includes a wheel-hub-facing face surrounding the axis and facing the end face, and a plurality of joining protrusions disposed on the wheel-hub-facing face and respectively complementary in shape with and respectively engage the engaging recesses.