Transmission Chain Curved Link Plates Lubrication
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Solution Overview
Problem
Conventional transmission chains experience increased friction and wear due to clearance between connecting pins and bushings, leading to the interruption of the lubricating oil film and increased contact points with the chain guide, resulting in higher sliding resistance and wear on the guide surfaces.
Innovation Solution
The transmission chain design includes bushings press-fitted into inner link plates and connecting pins press-fitted into outer link plates, with curved surfaces on the link plates' peripheral edges that adjust their widths to compensate for the clearance between the pin and bushing, ensuring that the contact points with the chain guide are minimized, thereby maintaining the lubricating oil film and reducing friction and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the transmission chain is designed with connecting pins and bushings in a loosely fitted state, then the bushings can rotate on the connecting pins during chain travel, but the clearance between them increases the spacing of contact points with the chain guide, causing interruption of the lubricating oil film and increased friction loss
Solution Approach 1:
The curved surfaces are pre-formed on the link plates with specific widths calculated to compensate for the maximum expected clearance between pins and bushings. This preliminary geometric configuration ensures that even when clearance causes displacement, the contact points remain within the curved surface boundaries, maintaining continuous lubrication without requiring active control during operation.
2Adaptability or versatility
If the clearance between connecting pin and bushing is increased, then the bushings can rotate more freely on the connecting pins, but the number of contact positions with the chain guide increases from two to four, increasing sliding resistance and wear
Solution Approach 1:
The widths of the curved surfaces are specifically designed as parameters that account for the maximum clearance value. By setting the curved surface widths to cover the range of possible contact point displacements caused by clearance, the design transforms the variable clearance into a manageable parameter that does not lead to increased wear or friction.
3Reliability
If the curved surface width on link plates is increased to compensate for clearance, then the lubricating oil film continuity is improved, but the structural strength of the link plates may be reduced
Solution Approach 1:
The curved surfaces are applied locally only on the specific regions of the link plates that contact the chain guide, rather than increasing the overall size or material properties of the entire link plate. This localized approach provides the necessary lubrication coverage while preserving the structural integrity and strength of the link plate in critical load-bearing areas.
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
This design reduces the sliding resistance and wear on the chain guide surfaces by minimizing the interruption of the lubricating oil film and maintaining the structural strength of the link plates, enhancing the chain's performance and longevity.
Implementation Method 1
interruption of the lubricating oil film between a traveling chain and a sliding curved surface of the chain guide
Implementation Method 2
sliding resistance of the chain can be reduced and an amount of wear on a sliding curved surface of a chain guide can be reduced
Data Source
AI summary
A transmission chain for a transmission having a drive sprocket and a driven sprocket with chain guides between the sprockets, at least one of the guides having a curved surface on which one of the runs of the chain slides in its travel between the sprockets. The chain has inner and outer link plates which respectively mount bushings and connecting pins which pass through the bushings with a clearance. The link plates have sliding surfaces which slide on the guide. The transmission chain has a chain pitch defined as P1, and the maximum clearance formed between the connecting pins and the bushings is defined as C. The sliding surfaces are curved like the guide and the curved surfaces of one of the outer and inner link plates, has a curve width X, and the curved surface of the other of the inner and outer link plates, has a curve width Y. The widths X and Y are selected relative to the chain pitch of P1 and the maximum clearance C to reduce or eliminate the loss of a film of lubricating oil between the sliding surfaces of the links and the curved surface of the guide as the chain travels from the drive sprocket to the driven sprocket.