Herringbone Gear Tooth Profile for Constant Meshing and Zero Sliding
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Solution Overview
Problem
Existing herringbone gear pairs have limited transmission efficiency, service life, and dynamic meshing performance due to large sliding ratios, time-varying meshing stiffness, and manufacturing costs associated with different cutters for convex and concave tooth profiles, leading to vibration noise and reduced bearing capacity.
Innovation Solution
A herringbone gear pair with a constant meshing characteristics constructed tooth pair using conjugate curves with continuous combined profiles, such as odd power function, sine, and epicycloid functions, allowing for the same tooth profile on both gears, reducing manufacturing costs and achieving zero sliding ratio, constant meshing stiffness, and symmetrical force action.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If involute gear pairs are used, then the gear structure is simple and easy to manufacture, but the sliding ratio is large leading to limited transmission efficiency and service life
Solution Approach 1:
The patent changes the fundamental geometric parameters of the gear tooth profile from involute to constructed tooth profiles based on conjugate curves. This parameter change reduces the sliding ratio during meshing while maintaining manufacturability through standardized construction methods, thereby improving transmission efficiency without sacrificing ease of manufacture
2Strength
If convex-tooth and concave-tooth gear pairs are used, then the bearing capacity is improved, but different cutters are required increasing manufacturing cost
Solution Approach 1:
The patent employs asymmetric constructed tooth profiles where both gears in the pair have identical or symmetric tooth profiles. This asymmetric design maintains the bearing capacity benefits of constructed profiles while eliminating the need for different cutters, as both gears can be manufactured using the same cutting tool and process
Solution Approach 2:
The patent creates homogeneity in the gear pair by making both gears have identical tooth profiles. This allows the use of the same cutter for both gears, reducing manufacturing cost while maintaining the improved bearing capacity characteristics of constructed tooth profiles
3Ease of manufacture
If conventional tooth profiles are used, then the manufacturing process is simple, but the meshing stiffness is time-varying causing vibration noise
Solution Approach 1:
The patent changes the tooth profile parameters to constructed profiles with specific geometric characteristics that enable constant meshing stiffness. This parameter change eliminates time-varying stiffness while maintaining manufacturing simplicity through standardized construction methods, thereby reducing vibration noise
4Device complexity
If the curvature radius at meshing point is limited, then the tooth profile is simple to construct, but the bearing capacity is limited
Solution Approach 1:
The patent changes the curvature parameters of the tooth profile by using constructed profiles based on conjugate curves. This allows for larger and more optimized curvature radii at meshing points, improving bearing capacity while maintaining reasonable construction complexity through systematic design methods
Data Source
AI summary
Provided is a herringbone gear pair with a constant meshing characteristics constructed tooth pair. The herringbone gear pair with a constructed tooth pair includes a herringbone gear I with a constructed tooth pair and a herringbone gear II with a constructed tooth pair based on conjugate curves. In the present disclosure, normal tooth profile curves of the herringbone gear pair with a constructed tooth pair are continuous combined curves with the same curve shape, which facilitates machining by the same cutter. A common normal at an inflection point or a tangent point of the continuous combined curve passes through a pitch point of the gear pair, and a position of the inflection point or the tangent point can be adjusted according to an actual demand. A contact ratio of the herringbone gear pair with a constructed tooth pair is designed as an integer.