Metal V-belt Flank Groove Pitch and Flatness Ratio
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Solution Overview
Problem
Existing metal V-belts in continuously variable transmissions suffer from inadequate frictional contact characteristics due to high bearing pressure concentrations, leading to excessive abrasion and reduced lubrication oil discharging efficiency, which compromises torque transmission efficiency.
Innovation Solution
A metal V-belt design featuring steel elements with a flatness ratio of the flank surface set to optimize machining and lubrication oil discharging, where the groove pitch is adjusted to balance production feasibility and effective oil discharging, resulting in a larger solid contact area and reduced bearing pressure, thereby enhancing torque transmission and extending belt life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fine grooves are formed on the flank surface of steel elements to discharge lubrication oil, then lubrication oil discharging effect is improved, but bearing pressure concentrates on raised portions causing excessive abrasion
Solution Approach 1:
The invention changes the geometric parameters of the flank surface by optimizing the flatness ratio (FR) to 70-85% and groove pitch (GP) to 0.05-0.15mm, which redistributes bearing pressure across the surface while preserving lubrication oil discharge capability through controlled groove placement
Solution Approach 2:
The invention applies different surface characteristics to different regions of the flank surface by creating a pattern of raised portions and grooves, where raised portions bear the load and grooves discharge lubrication oil, giving each region a specialized function that resolves the contradiction between pressure distribution and lubrication
2Power
If flatness ratio and groove pitch are optimized to increase solid contact area, then torque transmission efficiency is improved, but machining complexity increases
Solution Approach 1:
The invention establishes specific parameter ranges (flatness ratio 70-85%, groove pitch 0.05-0.15mm) that optimize torque transmission while remaining within practical machining capabilities, balancing performance improvement with manufacturing feasibility
Solution Approach 2:
The invention applies a moderate level of surface modification rather than extreme measures, using controlled groove patterns that provide sufficient lubrication discharge and pressure distribution without over-complicating the machining process
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 optimized design increases the solid contact area between the belt and pulleys, reducing abrasion and maintaining effective lubrication oil discharging, ensuring high torque transmission efficiency and prolonged belt usage.
Implementation Method 1
the flank (4a) of each steel element (4) comprises a plurality of equally spaced raised portions (41) each being placed between two grooves (42)... capable of causing the flank to exhibit a given lubrication oil discharging effect
Implementation Method 2
the flank (4a) capable of making frictional contact with the V-shaped groove for transmission of torque... there is effectively produced a protecting film of lubrication oil between flank surfaces of the steel elements and the conical faces of the drive and driven pulleys
Data Source
AI summary
Each steel element for a V-belt of a continuously variable transmission has a flank (4a) that comprises a plurality of equally spaced raised portions (41) each being placed between two fine grooves (42). A flat flatness ratio (FR) given by the equation (1) is set to the highest one of values that are capable of practically machining the flank (4a) of the steel element (4) and capable of causing the flank (4a) to exhibit a given and satisfied lubrication oil discharging effect, and a groove pitch (GP) that is a distance between the two fine grooves (42) is set to a value that is capable of practically machining the flank of the steel element and capable of causing the flank to exhibit a given and satisfied lubrication oil discharging effect. The groove pitch thus set is a value that is permitted by the higher value of the flatness ratio thus set.FR (%)=WRP/(WRP+WG)×100 (1)wherein:FR: Flatness ratioWRP: Width of the raised portion (41)WG: Width of the groove (42).