Vacuum Variable Capacitor Ball Screw End-Stop for Precise Tuning
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Solution Overview
Problem
Existing vacuum variable capacitors face challenges in achieving precise capacitance adjustment with low torque and reliable minimum capacitance definition, often requiring high torque motors and compromising on tunability and precision due to uncertain end-stop values defined by bellows compressibility.
Innovation Solution
A vacuum variable capacitor design incorporating a ball screw mechanism with a limiting element outside the vacuum sealed enclosure, allowing for precise definition of minimum capacitance through a nut shoulder abutting against the limiting element, enabling low torque adjustment of capacitance and precise reference values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If bellows compressibility is used to define minimum capacitance end-stop, then the mechanical drive system can be simplified, but the precision and reliability of minimum capacitance value deteriorates
Solution Approach 1:
A limiting element is introduced as an intermediary component between the bellows and the fixed plate. This limiting element serves as a mediator that provides a precise mechanical end-stop for the bellows compression, thereby defining the minimum capacitance value with high precision while keeping the mechanical drive system relatively simple.
2Force
If high torque motors are used to adjust capacitance, then the adjustment force is sufficient, but the device size and cost increase
Solution Approach 1:
The patent replaces the traditional direct-drive motor mechanism with a magnetic coupling system. The magnetic coupling transmits rotational motion from the motor to the movable plate without mechanical contact, reducing the torque requirements on the motor while maintaining sufficient adjustment force. This substitution allows for the use of smaller, lighter motors.
3Reliability
If bellows are used for mechanical coupling, then vacuum sealing is maintained, but the end-stop precision for minimum capacitance deteriorates
Solution Approach 1:
The mechanical coupling system is segmented into two distinct functional parts: the bellows component responsible for vacuum sealing and the limiting element component responsible for precise end-stop positioning. This segmentation allows each component to optimize its specific function without compromising the other.
Solution Approach 2:
The limiting element acts as an intermediary that interfaces with the bellows system to provide precise mechanical positioning. It translates the bellows compression into a defined end-stop position, thereby maintaining vacuum sealing integrity while achieving precise minimum capacitance definition.
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
Enables precise capacitance adjustment with reduced torque requirements, allowing for smaller and cheaper motors, and ensures consistent minimum capacitance values, enhancing reliability and performance in high-power applications like semiconductor manufacturing.
Implementation Method 1
the mechanical drive system comprises a ball screw arranged to drive the movable plate
Implementation Method 2
a vacuum sealed enclosure to contain a vacuum dielectric medium
Implementation Method 3
the movable plate is attached inside the enclosure to the second plate by means of at least one vacuum bellows
Data Source
AI summary
A vacuum variable capacitor includes a vacuum sealed enclosure to contain a vacuum dielectric medium, wherein the enclosure includes a first plate and a second plate, the first plate and the second plate being separated by an electrically insulating element, a fixed electrode attached inside the enclosure to the first plate and a movable electrode attached to a movable plate, wherein the movable plate is attached inside the enclosure to the second plate by at least one vacuum bellows, wherein the vacuum capacitor includes a mechanical drive system for displacing, in particular translating, the movable plate relative to the first plate so as to vary the capacitance of the vacuum capacitor, wherein the mechanical drive system includes a ball screw arranged to drive the movable plate and wherein the mechanical drive system includes outside of the vacuum sealed enclosure a limiting element limiting the maximum distance between the first plate and the movable plate and wherein the drive system includes a nut attached to the ball screw, wherein the nut includes a first shoulder configured to abut against the limiting element to limit the maximum distance between the first plate and the movable plate.