Planetary Gear and Carrier Assembly for Fatigue-Resistant Latching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing planetary gears face challenges in achieving high fatigue strength and ease of assembly while being cost-effective, particularly due to sensitivity of functional surfaces during assembly and the limitations of injection molding processes.
Innovation Solution
A planetary gear design with a wheel body featuring storage sections that can be inserted into corresponding recesses of a planet carrier, utilizing a bore that allows for assembly tool insertion without damaging functionally relevant surfaces, and incorporating ribs and starting projections to distribute loads and reduce stress, along with a planet carrier with elastic latching projections for quick and stable assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the planetary gear is manufactured from plastic using injection molding, then mass production capability and cost-effectiveness are improved, but the fatigue strength and maximum transmissible misuse torque deteriorate
Solution Approach 1:
The invention uses a hybrid construction where the planet gear body is made of plastic (injection-molded) but the bearing sections are made of metal (steel or aluminum alloy). This composite approach allows the majority of the component to be manufactured cost-effectively from plastic while the critical load-bearing areas utilize the high strength and fatigue resistance of metal materials, thereby resolving the contradiction between mass production capability and fatigue strength.
Solution Approach 2:
The invention applies different material properties to different parts of the planet gear: plastic for the gear body (where low cost and ease of manufacturing are priorities) and metal for the bearing sections (where high strength and fatigue resistance are critical). This localized material selection optimizes both manufacturing efficiency and mechanical performance, addressing the contradiction between productivity and strength.
2Productivity
If the planetary gear is designed for easy assembly, then assembly speed and productivity are improved, but the manufacturing precision of functional surfaces deteriorates
Solution Approach 1:
The planet gear is divided into two distinct segments: the injection-molded plastic gear body and the separately manufactured metal bearing sections. This segmentation allows each part to be optimized independently - the bearing sections can be precision-machined from metal with high surface accuracy, while the gear body is efficiently produced via injection molding. The separate manufacturing of critical surfaces resolves the contradiction between assembly speed and manufacturing precision.
Solution Approach 2:
The metal bearing sections act as intermediary components that bridge the plastic gear body and the planet carrier. These intermediary elements can be precisely manufactured and then quickly assembled, providing high-precision functional surfaces without compromising overall assembly speed. The bearing sections serve as mediators that decouple the manufacturing precision requirements from the assembly process.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The present invention relates to a planet gear (10) for a planetary gear set (14) with a planet gear bore (28) extending coaxially or parallel to the planet gear axis of rotation (APR), which at least partially passes through the planet gear axis (22). The invention further relates to a planet carrier (44) for such a planet gear (10), comprising a carrier body (46) with a first disk-shaped body (48) having at least one first bearing recess (60) having at least one circumferentially extending first locking projection (64), and with a second disk-shaped body (50) having at least one second bearing recess (62) having at least one circumferentially extending second locking projection (66).