Power Transmission Chain Pretension Loading via Roller Control
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Solution Overview
Problem
Existing methods for pretension loading of power transmission chains in continuously variable transmissions face challenges in consistently achieving a standard length with improved durability, often resulting in time-consuming processes and variable chain quality due to elastic and plastic deformations.
Innovation Solution
A method involving the controlled tension and displacement of rollers to maintain a chain in a substantial tension state, repeatedly measuring and adjusting the chain length until a predetermined difference from the target length is achieved, combined with a pretension loading apparatus featuring rotatable rollers, a displacement sensor, and a control unit to ensure precise length control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the chain is wound around two rollers and the rollers endlessly rotate the chain to load tensile load, then pretension is loaded on the chain, but it takes time to obtain a standard length of chain due to elastic and plastic deformations
Solution Approach 1:
The patent applies preliminary action by pre-stretching the chain to the target length before final assembly. The chain is stretched to a predetermined target length while maintaining tension, which eliminates the need for time-consuming iterative adjustments later. This preliminary stretching action ensures the chain achieves its final standard length efficiently, resolving the contradiction between durability improvement through pretension and time consumption.
Solution Approach 2:
The patent implements feedback control by measuring the actual length of the chain during the stretching process and comparing it with the target length. Based on this feedback, the tensioning force is adjusted to achieve the precise target length. This feedback mechanism ensures accurate length control while minimizing the time required to obtain a standard length chain, thereby improving both durability and production efficiency.
2Manufacturing precision
If the tensile load is controlled to be a predetermined value on the basis of the magnitude of the tensile load, then pretension is loaded on the chain, but it takes time to obtain a standard length of chain
Solution Approach 1:
The patent replaces the traditional mechanical tension control system with a more efficient system that combines mechanical tensioning with direct length measurement and control. Instead of relying solely on controlling tensile load magnitude over time, the system directly measures chain length and adjusts tension accordingly. This substitution of the control mechanism achieves precise chain length control while significantly reducing the time required to obtain a standard length chain.
3Manufacturing precision
If the chain is stretched repeatedly to achieve target length, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the tension force parameter during the stretching process based on real-time length measurements. Rather than using a complex multi-stage stretching apparatus, the system maintains a simple apparatus configuration while changing the tension parameter iteratively to achieve the target length. This approach improves manufacturing precision without significantly increasing device complexity, as the same apparatus can accommodate different tension levels.
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 approach allows for easy and secure attainment of a standard chain length with enhanced durability through residual stress application, simplifying operations and reducing manufacturing costs while improving yield.
Implementation Method 1
a plurality of link plates having a pair of pin holes are laminated so that the pin holes communicate with each other. Subsequently, the pin is inserted through the communicating pin holes, so that the plurality of link plates are bendably connected to each other to thereby configure a chain with an endless loop shape. Subsequently, pretension is loaded on the chain with an endless loop shape
Implementation Method 2
An example of chain deformation due to the load tension includes an elastic deformation and a plastic deformation
Implementation Method 3
An example of chain deformation due to the load tension includes an elastic deformation and a plastic deformation
Implementation Method 4
a displacement sensor that measures a displacement of the at least one of the rollers
Implementation Method 5
a control unit that controls the roller drive unit so that a length of the chain becomes a target length on the basis of a measurement value of the displacement sensor
Data Source
AI summary
There is provided a pretension loading method for a power transmission chain, in which a chain with an endless loop shape having a plurality of laminated link plates bendably connected to each other by pin members is wound around a plurality of rollers and the chain is endlessly rotated while a load is loaded on the chain so as to load pretension on the chain, the method including the steps of: (a) maintaining the chain in a substantial tension state without a slack by controlling tension of at least one of the plurality of rollers while endlessly rotating the chain; (b) measuring a length of the chain in the tension state; (c) stretching the chain to a target length by controlling a displacement of the at least one of the rollers; (d) maintaining the chain in a substantial tension state without a slack by controlling tension of the at least one of the rollers; and (e) measuring the length of the chain in the tension state. At this time, the steps (c) to (e) are repeated until a difference between the target length and the length of the chain which is measured in the step (e) is less than a predetermined value.