Rotating Bushing Chain Collar Locking to Prevent Link Walking
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Solution Overview
Problem
Existing track chain designs are susceptible to twisting and link walking due to high press fits and knurling, leading to integrity loss and seal damage, which compromises the useful life of the track chain.
Innovation Solution
A blind internal square section snap ring is used to axially lock each axially inner collar with its associated link, eliminating the need for knurling and high press fits, enhancing the strength of the connection and reducing assembly force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If knurling is applied to maximize press fit values between axially inner collars and links, then connection strength is improved, but device complexity and assembly difficulty increase
Solution Approach 1:
The connection mechanism is segmented into two distinct parts: a press fit connection and a snap ring retention connection. The snap ring provides a separate retention function that does not require knurling or complex surface treatments on the collar, thereby reducing device complexity while maintaining connection strength.
Solution Approach 2:
A snap ring is introduced as an intermediary component between the axially inner collar and the axially inner link. This snap ring acts as a mediator that provides the retention function without requiring complex surface treatments on the collar, thus reducing device complexity while maintaining the necessary connection strength.
2Reliability
If high press fits are used to prevent link walking, then connection reliability is improved, but assembly force requirements increase
Solution Approach 1:
The connection function is segmented into press fit for positioning and snap ring for retention. This segmentation allows the use of moderate press fit values that are easier to assemble while the snap ring provides the necessary retention reliability to prevent link walking.
Solution Approach 2:
The snap ring serves as an intermediary retention mechanism that reduces the force requirements for assembly. Instead of relying solely on high press fit forces, the snap ring provides a mechanical retention that maintains connection reliability with lower assembly forces.
3Stability of the object's composition
If knurling and high press fits are applied, then axial rigidity is improved, but local strains on chain components increase
Solution Approach 1:
The axial retention function is segmented from the press fit connection and assigned to the snap ring. This allows the press fit to provide positioning with reduced interference, thereby maintaining axial rigidity through the snap ring's mechanical retention while reducing local strains on the chain components.
4Strength
If high press fits and knurling are used, then connection strength is improved, but ease of manufacture deteriorates
Solution Approach 1:
The connection system is segmented into press fit for positioning and snap ring for retention. This segmentation eliminates the need for complex knurling operations, simplifying the manufacturing process while maintaining connection strength through the combined action of press fit and snap ring retention.
Solution Approach 2:
The snap ring acts as an intermediary component that simplifies manufacturing by providing a standard retention mechanism that does not require complex surface treatments like knurling. This intermediary component maintains connection strength while significantly improving ease of manufacture and assembly.
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 provides increased axial rigidity and reduces local strains on chain components, minimizing the risk of link walking and seal damage, while facilitating easier assembly and improving manufacturability and serviceability.
Implementation Method 1
expanding the resilient locking ring into the radially inward facing groove of the bore of the axially inner chain link
Implementation Method 2
a bushing journaled on an axially central portion of the pin for relative rotation between the bushing and the pin
Data Source
AI summary
An endless track chain includes a first and a second link set. Each link set includes two links. The links have aligned bores. A cartridge is received through the bores and connects the link sets to permit relative rotation therebetween. The cartridge includes a pin, a bushing journaled on the pin, first and second collars rotatably disposed on the pin on axially opposite sides of the bushing, and third and fourth collars disposed on the pin axially outboard of the first and second collars. The first and second collars are received in the bores of the first and second links and have axially form-fitting connections to the first and second links. The pin and the third and fourth collars are fixed relative to the third and fourth links.