Parabolic Tooth Trace Gear Mechanism for Reduced Frictional Wear
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Solution Overview
Problem
Conventional gear mechanisms face issues such as frictional wear, plastic deformation, thermal deformation, vibration, noise, and lubrication failures in extreme environments, leading to transmission failures and high costs, and existing designs like double-arc gears and hyperbolic circular arc gears have limitations in load-bearing capacity and tooth surface contact areas.
Innovation Solution
A parabolic tooth trace gear mechanism with a combined tooth profile of an end face circular arc and a parabola, featuring pure rolling meshing and symmetrical tooth surfaces, which extends the contact area across the tooth width and reduces relative sliding and frictional wear, utilizing a parabolic tooth trace structure with axisymmetric parabolas for improved load transmission and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional involute gear or helical gear is used, then the gear structure is simple and easy to manufacture, but the relative sliding of tooth surfaces causes frictional wear, gluing, plastic deformation, and transmission failure
Solution Approach 1:
The patent changes the fundamental parameter of tooth surface geometry from involute curve to parabolic curve with pure rolling meshing characteristic. This parameter change eliminates relative sliding between tooth surfaces, thereby preventing frictional wear, gluing, and plastic deformation while maintaining manufacturing feasibility through specialized cutting methods
Solution Approach 2:
The patent employs parabolic curved surfaces for tooth profiles instead of traditional involute curves. The parabolic curvature enables pure rolling contact between meshing teeth, transforming the sliding friction mechanism into rolling contact, which significantly reduces wear and improves transmission reliability
2Reliability
If gear lubrication system is added to reduce frictional wear, then the frictional wear is reduced, but the weight and cost of the whole machine increase
Solution Approach 1:
The patent converts the harmful relative sliding motion into beneficial pure rolling motion through parabolic tooth surface design. By eliminating sliding friction at the source, the system no longer requires external lubrication systems, thereby reducing machine weight and cost while maintaining high transmission reliability
Solution Approach 2:
The patent extracts and removes the lubrication system from the gear transmission mechanism by designing teeth that inherently eliminate sliding friction. This extraction eliminates the need for lubricants, lubrication pumps, and associated components, directly reducing system weight and complexity
3Shape
If double-arc gear mechanism is used, then the tooth profile can be designed with two arcs, but the pressure angles of two meshing points are defined to be equal which limits load-bearing capacity
Solution Approach 1:
The patent changes the tooth profile from double-arc with equal pressure angles to parabolic curve with variable pressure angles. This parameter change allows different pressure angles at different meshing points, optimizing stress distribution and significantly improving load-bearing capacity while maintaining the enhanced tooth profile shape
4Shape
If hyperbolic circular arc tooth trace cylindrical gear pair is used, then the tooth trace can be optimized, but the tooth tips become sharp and the effective contact area is concentrated only in the center of tooth width
Solution Approach 1:
The patent changes the tooth trace from hyperbolic circular arc to parabolic curve with specifically designed contact lines. This parameter change ensures that contact lines extend across the full width of the tooth, preventing sharp tooth tips and distributing contact area uniformly, thereby improving tooth contact strength and load-bearing capacity
Data Source
AI summary
The present disclosure provides a parabolic tooth trace gear mechanism with a combined tooth profile of an end face circular arc and a parabola, which belongs to the field of gear transmission. The parabolic tooth trace gear mechanism with the combined tooth profile of the end face circular arc and the parabola includes a small wheel and a big wheel geared externally with parallel axes, tooth surfaces of the small wheel and the big wheel both have a parabolic tooth trace structure, and both are formed by the motion of a combined tooth profile curve of an end face along a contact point, contact lines are all parabolas after being unfolded along a cylindrical surface, and the parabola is determined by a meshing line parameter equation and basic design parameters such as a coincidence degree, the number of teeth, a transmission ratio and the like. When correctly installed, at least one pair of gear teeth of the small wheel and the big wheel, implement pure rolling meshing contact at a node. The small wheel and the big wheel rotate when being driven by a driver to implement transmission between two shafts. The parabolic tooth trace gear mechanism with the combined tooth profile of the end face circular arc and the parabola according to the present disclosure has the advantages of a low frictional wear, a high transmission efficiency, a large single-stage transmission ratio, a strong bearing capacity and the like, and can be widely applied to a transmission system design of mechanical equipment.