Two-Crankshaft Linear Drive Using Reaction Torque for Valve Actuation
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Solution Overview
Problem
Existing linear drives for actuating valves in subsea applications are often too large or lack sufficient torque for their size, limiting their compactness and efficiency.
Innovation Solution
A compact linear drive design utilizing a planetary gear system with two crankshafts connected via connecting rods and a power-split configuration, where the reaction torque is utilized to enhance the overall torque output, allowing for a more compact and efficient conversion of rotational movement to linear movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional crank drive with a single crankshaft is used, then the linear drive can be kept simple in structure, but the torque output is insufficient for the same size
Solution Approach 1:
The single crankshaft is segmented into two crankshafts (first crankshaft and second crankshaft) that are driven by the planetary gear. Each crankshaft connects to the piston rod via its own connecting rod, allowing the system to generate higher torque output by distributing the driving force across multiple crankshafts while maintaining a relatively compact structure.
Solution Approach 2:
The planetary gear mechanism introduces an additional dimensional aspect to the power transmission system. By utilizing the planetary gear's ability to provide both speed reduction and torque multiplication in a compact configuration, the system achieves higher torque output without proportionally increasing the overall size or complexity.
2Volume of moving object
If the linear drive size is reduced for more compact design, then the overall dimensions are improved, but the torque output decreases
Solution Approach 1:
The planetary gear mechanism is nested within the linear drive structure, with the sun gear, planet gears, and ring gear arranged in a compact concentric configuration. This nesting allows the torque multiplication function to be integrated within the existing drive space, achieving higher torque output without increasing the overall linear drive size.
Solution Approach 2:
The planetary gear changes the torque parameter through its gear ratio. By selecting appropriate numbers of teeth for the sun gear, planet gears, and ring gear, the system can achieve significant torque multiplication while maintaining a compact size. The torque output is enhanced by leveraging the mechanical advantage provided by the planetary gear configuration.
3Power
If a planetary gear with fixed ring gear is used, then the gear structure is simple, but the reaction torque is wasted and not utilized for additional output
Solution Approach 1:
The reaction torque that would normally be wasted as a harmful force against the fixed ring gear is converted into a beneficial second output. By connecting the second crankshaft to the ring gear, the system transforms the reaction torque into useful work that drives the second connecting rod and piston rod, effectively doubling the useful torque output.
Solution Approach 2:
The ring gear serves multiple functions: it acts as both a gear element in the planetary transmission and as a driver for the second crankshaft. This multi-functionality allows the reaction torque to be utilized productively, enhancing the overall torque output while maintaining the simplicity of the planetary gear structure.
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 design achieves a higher torque output within a similar size, enabling a more compact and efficient linear drive that can effectively operate in deep water environments, such as oil or gas wells, by leveraging the sum of output and reaction torque, thus improving the drive's compactness and operational efficiency.
Implementation Method 1
a planetary gear for rotationally driving the first crankshaft and the second crankshaft
Implementation Method 2
a first crankshaft, which is connected to a piston rod via a first connecting rod
Data Source
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AI summary
Linear drive (100), in particular for converting a rotational movement into a linear movement for actuating a valve with a gate valve, with a crank mechanism, the linear drive (100) comprising a first crankshaft (6) which is connected to a piston rod (10) via a first connecting rod (8), a second crankshaft (7) which is connected to the piston rod (10) via a second connecting rod (9), and a planetary gear for rotary drive of the first crankshaft (6) and the second crankshaft (7).