Actuator With Inclined Threaded Element For Exhaust Valve
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Solution Overview
Problem
Existing actuators for exhaust gas recirculation valves and turbocharger components face challenges in efficiently converting rotary motion into translational motion while minimizing unintentional valve displacement due to gas forces and ensuring reliable operation under varying conditions.
Innovation Solution
The actuator features a rotatable threaded element with regions of differing pitch and an inclined rotational axis relative to the translational axis, allowing for high initial opening force followed by reduced force transmission, along with a single-stage gearing system and a spring element for fail-safe operation, and is designed to prevent unintentional rotation and enhance durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a uniform fine pitch is used throughout the threaded element, then high opening force is maintained throughout the stroke, but the rotational travel required becomes excessively large and the device complexity increases
Solution Approach 1:
The threaded element features varying pitch along its length, with a fine pitch region at the start of the stroke for high force transmission, and progressively coarser pitch regions toward the end for reduced rotational travel. This local differentiation optimizes force transmission where needed while minimizing overall rotation requirements.
2Device complexity
If the rotational axis of the threaded element is parallel to the translational axis of the output element, then the structure is simpler, but gas forces can cause unintentional rotation and valve displacement
Solution Approach 1:
The rotational axis of the threaded element is deliberately inclined at an angle between 5° and 15° relative to the translational axis of the output element. This asymmetric alignment creates a geometric relationship where gas forces acting on the valve cannot produce a moment that would cause unwanted rotation of the threaded element, thereby preventing unintentional valve displacement.
3Length of moving object
If a coarse pitch is used throughout the threaded element, then the rotational travel is reduced, but the opening force transmitted becomes insufficient, especially at the start of valve opening
Solution Approach 1:
The threaded element features varying pitch along its length, with a fine pitch region at the start of the stroke for high force transmission, and progressively coarser pitch regions toward the end for reduced rotational travel. This local differentiation optimizes force transmission where needed while minimizing overall rotation requirements.
4Force
If a multi-stage gearing system is used, then the force transmission is improved, but the response time increases and device complexity increases
Solution Approach 1:
The patent extracts and eliminates intermediate gearing stages, using a direct single-stage connection between the threaded element and the output element. This reduces the number of moving parts and transmission stages, thereby minimizing response delays while maintaining adequate force transmission through the optimized varying pitch thread design.
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 effectively prevents unintentional valve displacement, reduces response delays, and ensures reliable operation by transmitting forces perpendicular to the contact surface, enhancing the actuator's operating characteristics and durability.
Implementation Method 1
A rotary motion is converted into a translational motion of the valve element... the rotary motion is converted into a reciprocating motion essentially by means of a driven 'screw' comprising a thread in engagement with a fixed, but rotatable wheel
Data Source
AI summary
An actuator comprising a drive, at least one rotatable threaded element and at least one output element driven in translation thereby is described, characterized in that the threaded element has at least two regions of differing pitch and a rotational axis of the threaded element is inclined relative to a translational axis of the output element.