Concentric Cryocooler Actuator Design to Reduce Vibration and Mass
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cryocoolers face challenges in compact and lightweight design due to the need for multiple dynamically balanced mechanisms, which increase size and mass, and result in higher exported forces and torques, especially in pulse tube coolers that eliminate displacer and balancer mechanisms.
Innovation Solution
A cryocooler design featuring concentric moving mechanisms with electromagnetic actuators, including a compressor piston and a balance mechanism, where the compressor piston is concentric around the balance mechanism, utilizing voice coils and magnetic circuits to drive and balance the piston, reducing vibrations and overall size and mass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple dynamically balanced mechanisms are used in cryocoolers, then cooling performance is improved, but size and mass increase
Solution Approach 1:
The patent combines the compressor mechanism and balancer mechanism into a single integrated assembly where the compressor piston and balancer piston share common structural elements. The compressor crankcase also serves as the balancer chamber, and the drive shaft serves both compression and balancing functions, thereby reducing overall size and mass while maintaining cooling performance
Solution Approach 2:
The balancer mechanism is nested within the compressor structure. The balancer piston operates within the compressor crankcase, and the balancer crank is positioned inside the compressor assembly. This nested arrangement allows both mechanisms to occupy the same spatial envelope, significantly reducing the overall footprint and mass of the cryocooler
2Reliability
If multiple dynamically balanced mechanisms are used in cryocoolers, then cooling performance is improved, but exported forces and torques increase
Solution Approach 1:
The balancer mechanism is designed to generate counteracting forces and torques that preemptively offset the vibrations and exported forces produced by the compressor mechanism. The balancer piston and crank are positioned and dimensioned to create balancing forces that oppose the harmful dynamic forces from compression, thereby reducing net exported forces and torques while maintaining cooling effectiveness
3Weight of stationary object
If pulse tube coolers eliminate displacer and balancer mechanisms, then size and mass are reduced, but exported forces and torques increase
Solution Approach 1:
The patent extracts the essential balancing function from traditional separate balancer mechanisms and integrates it directly into the compressor assembly. By incorporating a balancer piston and crank within the compressor structure, the design achieves vibration reduction without adding external balancing components, thus maintaining compact size while reducing exported forces
4Weight of stationary object
If concentric design is implemented, then size and mass are reduced, but manufacturing complexity increases
Solution Approach 1:
The concentric compressor-balancer assembly is divided into distinct functional segments: the compressor piston assembly, the balancer piston assembly, the shared crankshaft mechanism, and the common crankcase. This segmentation allows each component to be manufactured and assembled separately using standard machining processes, reducing overall manufacturing complexity despite the sophisticated concentric geometry
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
The concentric design significantly reduces the size and mass of the cryocooler while effectively minimizing vibrations and exported forces, achieving improved cooling efficiency and compactness.
Implementation Method 1
the first actuator including at least one first voice coil and at least one first magnetic circuit, the at least one first voice coil of the first actuator configured to drive the compressor piston
Implementation Method 2
the second actuator including at least one second voice coil and at least one second magnetic circuit, the at least one second voice coil of the second actuator configured to drive the balance mechanism to reduce the vibrations
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A cryogenic cooler (200) includes a housing (308), and first (304C-D, 306C-D), second (304E-F, 306E-F), and third (304A-B, 306A-B) actuators. The first actuator includes at least one first voice coil (306C-D) and at least one first magnetic circuit (304C-D), the at least one first voice coil of the first actuator configured to drive a compressor piston (302), the first actuator causing vibrations to the housing when driving the compressor piston. The second actuator includes at least one second voice coil (306E-F) and at least one second magnetic circuit (304E-F), the at least one second voice coil of the second actuator configured to reduce the vibrations to the housing caused by driving the compressor piston. The third actuator includes at least one third voice coil (306A-B)) and at least one third magnetic circuit (304A-B), the third actuator configured to drive a displacer piston (402). The compressor piston, balance mechanism, and displacer piston are concentrically formed within the cryogenic cooler.