Link-Plate Chain Cradle Thrust Piece Elastic Deformation
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Solution Overview
Problem
Existing link-plate chains for v-pulley-continuously variable transmissions experience uneven tension distribution and increased wear due to deflection under high loads, leading to instability and noise, particularly during partial load operations.
Innovation Solution
The cradle thrust pieces are designed with outer rolling surfaces that allow outer links to be relieved at low loads and loaded in the elastic deformation region at full loads, ensuring uniform tension distribution and stability, with conical tapering to maintain defined contact and damping behavior across the load range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inner rolling surfaces of the cradle thrust pieces are made as free-form surfaces to compensate tension differences, then wear of outside links is reduced, but spot contact occurs at low loads causing instability and increased wear
Solution Approach 1:
The cradle thrust pieces are designed with different surface geometries for different regions: the inner rolling surfaces have free-form surfaces to compensate tension differences across the width, while the outer rolling surfaces have specific geometries (conical or with radius of curvature) to ensure line contact. This local differentiation allows each region to fulfill its specific function - the inner surfaces handle tension distribution while the outer surfaces maintain stable contact.
Solution Approach 2:
The patent introduces elastic deformation capability to the cradle thrust pieces, allowing them to dynamically adapt to varying load conditions. At low loads, the elastic deformation maintains line contact through the outer rolling surfaces; at full loads, the elastic deflection shifts loading to external links. This dynamic behavior resolves the contradiction between wear resistance and running stability.
2Strength
If the cradle thrust pieces are made thicker in the middle area to counteract deflection under high loads, then outer links are protected from overloading, but only spot contact occurs at low loads causing instability
Solution Approach 1:
The cradle thrust pieces are designed with different surface geometries for different regions: the inner rolling surfaces have free-form surfaces to compensate tension differences across the width, while the outer rolling surfaces have specific geometries (conical or with radius of curvature) to ensure line contact. This local differentiation allows each region to fulfill its specific function - the inner surfaces handle tension distribution while the outer surfaces maintain stable contact.
Solution Approach 2:
The patent introduces elastic deformation capability to the cradle thrust pieces, allowing them to dynamically adapt to varying load conditions. At low loads, the elastic deformation maintains line contact through the outer rolling surfaces; at full loads, the elastic deflection shifts loading to external links. This dynamic behavior resolves the contradiction between wear resistance and running stability.
3Reliability
If the outer rolling surfaces are made conical to relieve outer links at low load, then tension distribution is improved, but manufacturing complexity increases
Solution Approach 1:
The cradle thrust pieces are designed with different surface geometries for different regions: the inner rolling surfaces have free-form surfaces to compensate tension differences across the width, while the outer rolling surfaces have specific geometries (conical or with radius of curvature) to ensure line contact. This local differentiation allows each region to fulfill its specific function - the inner surfaces handle tension distribution while the outer surfaces maintain stable contact.
Solution Approach 2:
The patent modifies the geometric parameters of the outer rolling surfaces (conical shape or radius of curvature) to optimize tension distribution across different load conditions. This parameter change allows the outer links to be relieved at low loads while maintaining manufacturing feasibility through standard machining operations.
4Reliability
If the cradle thrust pieces are designed to load all links at full load, then uniform tension is achieved, but the structure becomes more complex
Solution Approach 1:
The cradle thrust pieces are designed with different surface geometries for different regions: the inner rolling surfaces have free-form surfaces to compensate tension differences across the width, while the outer rolling surfaces have specific geometries (conical or with radius of curvature) to ensure line contact. This local differentiation allows each region to fulfill its specific function - the inner surfaces handle tension distribution while the outer surfaces maintain stable contact.
Solution Approach 2:
The patent introduces elastic deformation capability to the cradle thrust pieces, allowing them to dynamically adapt to varying load conditions. At low loads, the elastic deformation maintains line contact through the outer rolling surfaces; at full loads, the elastic deflection shifts loading to external links. This dynamic behavior resolves the contradiction between wear resistance and running stability.
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 configuration reduces wear and noise, enhances stability, and ensures uniform tension application to all links, improving the overall performance and durability of the link-plate chain.
Implementation Method 1
the links of the link-plate chain which lie outside when viewed in the transverse direction are relieved at low load and at full load are loaded at the same time in the elastic deformation region of the cradle thrust pieces
Implementation Method 2
the proposed configuration of the cradle thrust pieces with the correspondingly made outer rolling surfaces can achieve improved damping behavior of the link-plate chain by microslip between the adjacent links
Data Source
AI summary
The invention relates to a link-plate chain for a v-pulley-continuously variable transmission, especially for motor vehicles, with several cradle thrust pieces configured in pairs and projecting transversely through the link-plate chain, and links which are offset to each other and which connect the cradle thrust pieces in the lengthwise direction of the chain, the cradle thrust pieces adjoining each other with the inner rolling surfaces facing each other and interacting with outer rolling surfaces with openings of the links and on their front sides having friction surfaces which run onto the annular surfaces of the v-pulleys to transmit torque, and furthermore the cradle thrust pieces being made such that the differences of the torque transmitted by way of the cradle thrust piece pairs to the links, which differences are present over the width of the link-plate chain, are at least partially compensated. To obtain a link-plate chain with low wear and improved stability of running, the outer rolling surfaces of at least one of the respective cradle thrust pieces, but preferably of both cradle thrust pieces, are made such that the links of the link-plate chain which lie outside when viewed in the transverse direction are relieved at low load and at full load are loaded at the same time in the elastic deformation region of the cradle thrust pieces.