Cammed Ball Screw Clutch for Low-Power Downhole Valve Actuation
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Solution Overview
Problem
Current subsurface safety valve linear actuators face challenges due to size and power limitations, leading to inadequate torque in clutches, and high power consumption and temperatures that affect reliability.
Innovation Solution
The use of a cammed ball screw mechanism in electro-mechanical assemblies, which replaces the electromagnetic clutch and brake, minimizing electrical components and reducing stress on actuator components by removing the holding load from the guide rod assembly, allowing for efficient operation of subsurface safety valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a clutch is used in the linear actuator, then the valve can be controlled, but the torque requirements cannot be achieved due to size and power limitations
Solution Approach 1:
The patent removes the clutch and brake components from the actuator assembly, extracting the problematic mechanical elements that consumed excessive power and occupied space. The holding load function is transferred to the guide rod assembly, eliminating the need for a clutch in the traditional sense.
Solution Approach 2:
The patent replaces the electromagnetic clutch-brake system with a mechanically-oriented guide rod and cam assembly. This substitution eliminates the need for complex electromagnetic engagement mechanisms while achieving the same functional outcome through mechanical means.
2Reliability
If a clutch is used in the linear actuator, then the valve can be controlled, but power consumption and temperatures are high affecting reliability
Solution Approach 1:
The patent removes the clutch and brake components from the actuator assembly, extracting the problematic mechanical elements that consumed excessive power and occupied space. The holding load function is transferred to the guide rod assembly, eliminating the need for a clutch in the traditional sense.
Solution Approach 2:
The guide rod assembly provides self-holding capability through its mechanical design, eliminating the need for continuous power consumption to maintain position. The system uses its own structural features (guide rod, cam, track) to maintain the valve position without requiring active clutch engagement.
3Strength
If a clutch is used in the linear actuator, then the valve can be controlled, but the holding load stresses the actuator components
Solution Approach 1:
The patent removes the clutch and brake components from the actuator assembly, extracting the problematic mechanical elements that consumed excessive power and occupied space. The holding load function is transferred to the guide rod assembly, eliminating the need for a clutch in the traditional sense.
Solution Approach 2:
The guide rod assembly acts as an intermediary element that bears the holding load, transferring the force from the valve mechanism to the track structure. This intermediary structure protects the main actuator components from excessive stress while maintaining control capability.
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 enhances the reliability and efficiency of subsurface safety valves by reducing power requirements and stress on components, enabling effective opening and closing of the valves with a minimum number of electrical components.
Implementation Method 1
a ball screw; a ball nut disposed around the ball screw
Implementation Method 2
a cam disposed around the ball nut; stopping rotation of the cam to extend the cam axially
Implementation Method 3
a spring-loaded rail that is disposed in a track and that stops rotation of the cam to extend the cam axially
Data Source
AI summary
Systems and methods of the present disclosure relate to actuator assemblies for downhole tools. An actuator assembly comprises a ball screw; a ball nut disposed around the ball screw; a cam disposed around the ball nut; a rail disposed adjacent to the cam, the rail operable to stop rotation of the cam to extend the cam axially as the ball nut traverses the ball screw.