Variable Pressure-Angle Gear Pair for Smooth Meshing Strength
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Solution Overview
Problem
Conventional gear pairs, such as those described in Patent Document 1, fail to consider pressure angle settings in tooth profile curves, leading to insufficient smooth meshing and reduced tooth strength, particularly on the tooth-root side where surface pressure strength decreases due to increasing relative curvature.
Innovation Solution
A gear pair design where the meshing line is shared between a first gear with fewer teeth and a second gear with more teeth, with a pressure angle that is not constant along the meshing line, specifically increasing on the tooth-root and tooth-top sides, and varying in sections to manage relative curvature and contact stiffness, ensuring smooth meshing and increased strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the meshing line is shared between two gears to ensure smooth meshing, then the meshing smoothness is improved, but the relative curvature increases on the tooth-root side causing reduced surface pressure strength
Solution Approach 1:
The invention changes the pressure angle parameter from a constant value to a variable that increases from the pitch point toward the tooth-root side. This parameter change allows the tooth profile curvature to be adjusted, reducing the relative curvature at the tooth-root contact region and thereby increasing the surface pressure strength while maintaining the shared meshing line configuration
2Strength
If the pressure angle is increased on the tooth-root side to reduce relative curvature and increase surface pressure strength, then the tooth strength is improved, but the meshing smoothness may be compromised
Solution Approach 1:
The invention applies local quality by making the pressure angle variable rather than uniform. The pressure angle is specifically increased in the tooth-root region where strength is needed, while maintaining appropriate values in other regions. This localized parameter adjustment improves surface pressure strength at the critical tooth-root contact zone without adversely affecting the overall meshing smoothness
3Ease of manufacture
If conventional tooth profile curves are used without considering pressure angle variation, then the manufacturing is simpler, but the tooth strength and meshing performance are insufficient
Solution Approach 1:
The invention introduces dynamics by making the pressure angle a variable parameter that changes along the tooth profile, specifically increasing from the pitch point toward the tooth-root side. This dynamic parameter adjustment optimizes both the strength characteristics and meshing performance of the gear teeth, overcoming the limitations of conventional static pressure angle designs while remaining manufacturable
Data Source
AI summary
In a gear pair in which a first gear and a second gear having a larger number of teeth than the first gear share a meshing line (L) of teeth that mesh with each other, at least a part of the meshing line (L) includes a region where a pressure angle (a) is not constant, and the pressure angle (α) weakly increases in a section of the meshing line (L) from a pitch point (Pp) to an end point (Pe1) on a tooth-root side of the first gear (G1). This allows both desired properties (for example, strength) and smooth meshing to be achieved, and also allows effective increase in strength of the tooth-root side of the gear having the small number of the teeth (that is, the first gear) subject to a large load and susceptible to damages on the tooth-root side.