Planetary Gear Thrust Washer Geometric Fixing
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Solution Overview
Problem
In planetary gear transmissions, thrust washers that are not fixedly bonded to gear parts can move relative to the annulus gear, leading to wear and premature failure due to contact with gear teeth, and bonding them requires additional resources and process complexity.
Innovation Solution
A thrust washer with geometrically designed protrusions or recesses that engage with gear parts to secure its position without the need for adhesives, using radial protrusions on the outside or inside circumference to prevent rotation and contact with gear teeth, and recesses to engage with planetary wheel bearings for fixed support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the thrust washer is not fixed or bonded to the annulus gear, then the manufacturing process is simpler and costs are lower, but the thrust washer moves relative to the annulus gear causing wear and premature failure
Solution Approach 1:
The thrust washer is segmented with protrusions or recesses that engage with corresponding features on the annulus gear. This segmentation allows the thrust washer to be a simple pressed part without bonding, while the engaging features prevent relative movement and ensure reliable operation.
Solution Approach 2:
The thrust washer's own geometry (protrusions or recesses) provides the fixing function. The component serves itself by incorporating fixing features directly into its structure, eliminating the need for external bonding agents or additional fixing components.
2Reliability
If the thrust washer is bonded to the annulus gear, then the thrust washer is securely fixed in position, but additional materials and process steps are required increasing cost and manufacturing time
Solution Approach 1:
The bonding function is extracted and replaced by geometric engaging features (protrusions or recesses) that are integral to the thrust washer structure. This eliminates the need for adhesive materials and bonding process steps while maintaining secure positioning.
Solution Approach 2:
The chemical bonding system (adhesive) is replaced by a mechanical engagement system (protrusions or recesses). The geometric features provide mechanical interlocking that secures the thrust washer without requiring chemical bonding processes.
3Reliability
If the thrust washer is bonded to the annulus gear, then the thrust washer remains stationary during operation, but the bonding process greatly prolongs the manufacturing cycle
Solution Approach 1:
The fixing features (protrusions or recesses) are pre-formed as integral parts of the thrust washer during its initial pressing process. This preliminary incorporation of fixing features eliminates the need for subsequent bonding operations, thereby shortening the manufacturing cycle while ensuring stable operation.
Solution Approach 2:
The fixing function is merged with the thrust washer's geometric structure. The protrusions or recesses are combined with the thrust washer body in a single pressing operation, eliminating separate bonding steps and reducing overall manufacturing time.
Data Source
AI summary
A central thrust washer for all planets of a planetary carrier of a planetary gear that is geometrically designed such that it engages in recesses in the annulus gear or the drive wheel or is connected to planetary wheel bearings of the planetary carrier so as to prevent any relative movement. For this purpose, at least one fixing element is provided on the thrust washer.