Integral Planetary Gear Ball Valve for Low-Backlash Actuation
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Solution Overview
Problem
Existing ball valve systems with epicyclic or planetary gear trains are complex, leading to increased size, mass, and risk of mechanical failure due to multiple parts, as well as backlash in the drive system, which complicates precise positioning and packaging, especially in aerospace applications where space and weight are critical.
Innovation Solution
Integrally forming a gear of the planetary gear set with the valve body reduces the number of parts, minimizes backlash, and allows for conventional polishing, thereby simplifying the drive system and enhancing precision and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a planetary gear train with multiple separate parts is used, then torque multiplication and controlled rotation are achieved, but device complexity, size, and mass increase
Solution Approach 1:
The patent merges the ring gear with the valve body into a single integral component, eliminating the need for a separate ring gear part. This reduces the total number of parts in the planetary gear train while maintaining the torque multiplication function through the remaining sun gear, planet gears, and carrier assembly.
2Power
If multiple separate gear components are used, then the planetary gear function is achieved, but backlash and risk of mechanical failure increase
Solution Approach 1:
By integrating the ring gear teeth directly into the valve body as an integral feature rather than a separate component, the patent eliminates interfaces and potential failure points between the ring gear and other gear elements. This reduces backlash and improves reliability by ensuring precise geometric relationships and eliminating loose tolerances between separate parts.
3Power
If multiple separate parts are used in the drive system, then the planetary gear mechanism is achieved, but space and mass increase
Solution Approach 1:
The integration of the ring gear with the valve body into a single component reduces the total part count and eliminates the need for additional fasteners, bearings, and mounting structures that would be required for a separate ring gear. This consolidation directly reduces the overall mass of the moving valve system while maintaining the planetary gear mechanism's torque multiplication capability.
4Power
If a separate ring gear is used, then the planetary gear set is complete, but manufacturing precision and polishing become more difficult
Solution Approach 1:
By making the ring gear an integral feature of the valve body, the patent allows the entire valve body and ring gear to be manufactured and polished as a single monolithic component. This ensures consistent geometric precision and surface finish across all gear interfaces without the alignment and matching difficulties that would arise from assembling multiple separate precision parts.
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
This configuration results in a more compact, lighter, and reliable ball valve system with improved precision and reduced risk of mechanical failure, suitable for aerospace applications like gas turbine engine refuel manifolds, where space and weight are critical.
Implementation Method 1
a shaft connected to the valve body can be directly rotated (by means such as a handwheel or a motor). However, rather than direct drive, it is common for some form of epicyclic gear train or planetary gear to be used in the drive train
Implementation Method 2
a gear of the planetary gear set is integrally formed with the valve body
Data Source
AI summary
A ball valve includes a valve body. The valve body is driven to rotate through a drive train that includes a planetary gear set. A gear of the planetary gear set is integrally formed with the valve body. In an embodiment, a ring gear of the planetary gear set is integrally formed with the valve body.