Oval Gear Teeth Involute Profile Fluid Metering
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Solution Overview
Problem
Conventional gear tooth designs for oval gears in fluid metering devices face challenges such as fluid leakage, noise, vibration, and manufacturing complexities due to the impracticality of using conventional hobbing processes for producing involute teeth, which often result in trade-offs between performance and manufacturability.
Innovation Solution
The design of an oval gear set with identical gears that mesh at a fixed center-to-center distance, featuring a hub with gear teeth having circular involute curve profiles, which facilitates smooth rolling and sealing, reducing fluid leakage and improving manufacturability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional hobbing processes are used to produce involute gear teeth for oval gears, then manufacturing complexity increases and manufacturing precision deteriorates due to the need for translating the gear blank and undercutting of teeth
Solution Approach 1:
The patent changes the fundamental parameter of the tooth profile from conventional involute to circular arc, which allows oval gears to be manufactured using standard hobbing processes without requiring complex blank translation or specialized cutters. This parameter change eliminates the manufacturing precision problems associated with conventional involute teeth on oval gears.
Solution Approach 2:
The patent adopts a tooth profile design that can be produced with standard, readily available hobbing equipment rather than requiring specialized or custom tooling. This makes the manufacturing process more accessible and reduces the need for expensive, complex manufacturing setups.
2Reliability
If gear teeth are designed to smoothly roll against each other, then reliability improves through reduced noise and vibration, but device complexity increases due to the need for precise tooth geometry
Solution Approach 1:
The patent changes the tooth profile parameter from involute to circular arc, which simplifies the geometry while still enabling smooth rolling contact between mating gears. The circular arc profile is inherently simpler to define and manufacture while maintaining the essential rolling action that reduces noise and vibration.
Solution Approach 2:
The patent uses identical circular arc tooth profiles on both mating gears, creating a homogeneous and symmetrical gear pair design. This symmetry simplifies the overall system design and ensures uniform performance characteristics.
3Object-generated harmful factors
If gear teeth use involute surfaces for smooth rolling, then object-generated harmful factors are reduced through decreased noise and vibration, but ease of manufacture deteriorates due to manufacturing complexities
Solution Approach 1:
The patent changes the tooth profile from involute to circular arc, which maintains the smooth rolling action that reduces noise and vibration while dramatically improving ease of manufacture. The circular arc profile can be produced with standard hobbing processes without the complexities of blank translation or specialized tooling.
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 involute gear teeth design enhances the accuracy and longevity of fluid metering devices by preventing fluid blow-by, reducing noise and vibration, and allowing for uniform fluid flow across a wide range of dispensing rates, while being easier to manufacture.
Implementation Method 1
involute gear tooth surfaces, which tend to roll across each other as the gears rotate, rather than sliding and chattering against each other
Implementation Method 2
the accuracy with which the metering mechanism is able to determine flow depends on the ability of the tooth interface to seal and prevent fluid leakage between the gears
Data Source
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AI summary
An oval gear set 46 for use in a flow meter 28 comprises first and second gears (46A, 46B) that are identical to each other and that are configured to engage at a fixed center-to-center distance CD such that the first and second gears (46A, 46B) mesh at all angular positions. Each gear of the oval gear set 46 comprises a hub and a plurality of gear teeth 95. The hub comprises an oval body (99A, 99B) having a major axis and a minor axis extending through a center (100A, 100B) of the hub, and a root profile RP wall circumscribing the major and minor axes. The plurality of gear teeth 95 extend from the root profile RP wall. Each of the gear teeth 95 has a pair of contact surfaces with circular involute curve profiles (IC1, IC2).