Ball Screw Linear Actuator for Compact High-Force Subsea Motion
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Solution Overview
Problem
Existing systems for converting rotational motion into linear motion, such as hydraulic and pneumatic systems, are inefficient and large in size, making them unsuitable for compact applications like subsea operations, where high precision and reliability are required.
Innovation Solution
A compact ball screw linear actuator system with recirculating bearing balls is used, where the outer lead-screw is fixed and the inner lead-screw is non-rotating, allowing for efficient and accurate conversion of rotational motion to linear motion, and includes a mechanical override mechanism for reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If hydraulic systems are used to transfer high force in compact systems, then high force transfer capability is achieved, but system efficiency is low and building size is large
Solution Approach 1:
The patent replaces the hydraulic mechanical system with an electric motor-driven ball screw mechanism. The electric motor converts electrical energy to rotational motion, which is then transformed into linear motion through the ball screw and nut assembly. This substitution eliminates hydraulic fluid, pumps, and valves, significantly improving system efficiency while maintaining compact dimensions and high force transfer capability through the mechanical advantage of the ball screw threads.
2Force
If hydraulic systems are used to transfer high force in compact systems, then high force transfer capability is achieved, but building size is large
Solution Approach 1:
The electric motor and ball screw assembly occupy significantly less volume than hydraulic components (pump, reservoir, valves, hoses). The ball screw mechanism provides high force multiplication in a compact cylindrical form factor, enabling the actuator to fit in spaces where hydraulic systems would be too bulky.
3Power
If conventional ball screw and nut assembly with single-file row of balls is used, then rotational torque is converted to linear force, but frictional resistance is high and operation is not smooth
Solution Approach 1:
The patent transitions from a single-file row of balls to a multi-row ball arrangement within the nut. Multiple rows of balls distribute the load across parallel pathways, reducing friction and enabling smoother operation. The balls are contained within a course or sized structure that accommodates multiple rows, allowing simultaneous rolling contact across several ball rows as the screw rotates relative to the nut.
4Duration of action of moving object
If ball recirculation system is added to ball screw mechanism, then continuous operation is enabled, but device complexity increases
Solution Approach 1:
The ball recirculation system is merged with the ball screw and nut assembly by integrating the ball course and return pathway directly into the nut structure. The course or sized containment structure for the balls is incorporated as part of the nut body, eliminating the need for separate external recirculation mechanisms. This integration maintains compact design while enabling continuous ball recirculation for sustained operation.
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 solution enables more efficient and accurate subsea operations by replacing hydraulic systems with electrical power, allowing for compact, reliable, and precise linear actuation, suitable for both land and subsea environments, with a mechanical override for contingency operations.
Implementation Method 1
a follower nut or nut with a mating continuous helical groove or thread that cooperates with the external groove of the leadscrew to form a course or sized to contain a single-file row of plurality of balls, which operate in rolling contact with both the lead-screw groove and follower (or nut) groove
Data Source
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AI summary
This invention generally concerns the field of linear actuator in a cylindric housing. More particular, the present disclosure relates to a ball screw driven linear actuator for converting rotational movement into linear movement, and vice versa. The present disclosure has use to applications requiring high performance, high force and speed. This invention is performing both at surface and subsea