Adjustable Planetary Gearset for Servo Valve Torque Control
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Solution Overview
Problem
Existing servomotor systems with manual control mechanisms for valves do not effectively account for the varying force requirements during valve closure, primarily focusing on the short high-force phase without consideration for the longer approach phase, leading to inefficient operation.
Innovation Solution
An epicyclic gear train with adjustable speed transmission ratios is used, allowing for a multiplication of revolutions during the approach phase and a direct transmission during the closing phase, utilizing a rotatable ring gear and planet carrier with external toothing and a control pinion to manage gear ratios, enabling efficient torque distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed gear ratio is used in the planetary gearset, then the structure is simple, but it cannot adapt to the varying torque requirements during valve operation
Solution Approach 1:
The planetary gearset implements a dynamic gear ratio changing mechanism where the ring gear can be selectively locked or unlocked. When unlocked, the ring gear allows the planet carriers to rotate independently, providing a first gear ratio suitable for the approach phase. When locked, it constrains the planet carriers to rotate together with the ring gear, providing a second gear ratio for the closing phase. This dynamic reconfiguration enables the system to adapt to varying torque requirements without excessive complexity.
Solution Approach 2:
The system changes the transmission ratio parameter based on the operational phase. During the approach phase, the gearset operates in a first transmission ratio mode that provides mechanical advantage for the longer duration. During the closing phase, it switches to a second transmission ratio mode that provides different mechanical characteristics for the high-force operation. This parameter change is achieved through the selective locking of the ring gear, allowing the system to optimize performance for each phase.
2Productivity
If the manual control mechanism is designed solely for the short high-force closing phase, then it is optimized for that phase, but it is inefficient during the much longer approach phase
Solution Approach 1:
The valve operation is segmented into two distinct phases: the approach phase and the closing phase. The planetary gearset is designed with two corresponding transmission ratios to optimize performance for each phase. The first transmission ratio is optimized for the approach phase where the valve member moves toward the seat, providing efficient mechanical advantage for the longer duration operation. The second transmission ratio is optimized for the closing phase where high force is required to seat the valve, ensuring ease of operation despite the shorter duration.
3Productivity
If a single gear ratio is used throughout the entire valve closure process, then the mechanism is simple, but it cannot optimize performance for both the approach phase and closing phase
Solution Approach 1:
The planetary gearset implements a dynamic gear ratio changing mechanism where the ring gear can be selectively locked or unlocked. When unlocked, the ring gear allows the planet carriers to rotate independently, providing a first gear ratio suitable for the approach phase. When locked, it constrains the planet carriers to rotate together with the ring gear, providing a second gear ratio for the closing phase. This dynamic reconfiguration enables the system to adapt to varying torque requirements without excessive complexity.
Data Source
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AI summary
The invention relates to an epicyclic gear train, advantageously for a servomotor system, of the type comprising, arranged in a housing (18), a planet carrier (24) carrying a plurality of planets (26), a ring (28), and a sun gear (30). The epicyclic gear train is characterized in that it includes means (40) for changing the speed ratio between the input and output, which are actuable from outside the housing (18). The invention is applicable in servomotor systems.