Constructed Cylindrical Gear Pair for Constant Meshing Stiffness
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Solution Overview
Problem
Existing external meshing cylindrical gear pairs face issues such as large sliding ratio, time-varying meshing stiffness, and high manufacturing costs, which affect transmission efficiency, service life, and dynamic meshing performance, making them unsuitable for high-performance applications in fields like national defense and industrial manufacturing.
Innovation Solution
The design of an external meshing cylindrical gear pair with a constant meshing characteristics constructed tooth pair, featuring a cylindrical gear I and gear II with the same normal tooth profile, constant curvature radius, and constant sliding ratio, achieved through continuous combined curves of specific functions, allowing for the use of a single cutter and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional involute gear pairs are used, then the gear pair can transmit power and change rotation direction, but the sliding ratio between tooth surfaces is large and meshing stiffness is time-varying, leading to reduced transmission efficiency and service life
Solution Approach 1:
The patent changes the fundamental geometric parameters of the gear tooth profile from conventional involute curves to constructed tooth profiles based on conjugate curves. This parameter change results in constant meshing stiffness and reduced sliding ratio, directly improving both transmission efficiency and service life simultaneously
Solution Approach 2:
The patent introduces dynamic balance to the meshing process by designing the constructed tooth profile such that meshing stiffness remains constant throughout the engagement cycle. This eliminates the time-varying stiffness characteristic of involute gears, reducing vibration and improving both efficiency and reliability
2Strength
If gears with concave and convex tooth profiles are used to achieve multi-point contact, then bearing capacity may be improved, but different cutters are required for machining, increasing manufacturing cost
Solution Approach 1:
The patent applies homogeneity by designing both gears in the pair with identical constructed tooth profiles based on the same conjugate curves. This allows both gears to be manufactured using the same cutter and processing parameters, eliminating the need for different cutters while maintaining enhanced bearing capacity through the optimized profile geometry
Solution Approach 2:
The constructed tooth profile serves multiple functions simultaneously: it provides enhanced bearing capacity through optimized contact geometry, enables manufacturing with a single universal cutter, and achieves constant meshing stiffness. This multi-functionality resolves the contradiction between strength and manufacturing ease
3Ease of manufacture
If constructed tooth pairs with convex-convex contact based on conjugate curves are used, then manufacturing cost may be reduced, but the curvature radius at meshing point is limited and meshing stiffness is time-varying, intensifying vibration noise
Solution Approach 1:
The patent optimizes the parameters of the constructed tooth profile by selecting appropriate conjugate curves and design variables to achieve constant meshing stiffness. This parameter optimization eliminates time-varying stiffness while maintaining the manufacturing advantages of constructed tooth pairs, thereby reducing vibration noise
Solution Approach 2:
The patent introduces dynamic balance to the meshing process through the constructed tooth profile design, making meshing stiffness constant throughout the engagement cycle. This eliminates the time-varying stiffness that causes vibration and noise, while preserving the manufacturing simplicity of constructed tooth pairs
4Ease of manufacture
If constructed tooth pairs with same normal tooth profile are used, then manufacturing cost is reduced and bearing capacity is improved, but sliding ratio was not optimized, affecting transmission efficiency
Solution Approach 1:
The patent simultaneously optimizes multiple parameters of the constructed tooth profile including the conjugate curve equations, design variables, and geometric characteristics. This comprehensive parameter optimization achieves both reduced sliding ratio for improved efficiency and constant meshing stiffness, while maintaining the manufacturing advantage of identical tooth profiles
Data Source
AI summary
Provided is an external meshing cylindrical gear pair with a constant meshing characteristics constructed tooth pair. The external meshing cylindrical gear pair with a constructed tooth pair includes a cylindrical gear I with a constructed tooth pair and a cylindrical gear II with a constructed tooth pair based on conjugate curves. In the present disclosure, normal tooth profile curves of the cylindrical gear I with a constructed tooth pair and the cylindrical gear II 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 is designed as an integer.