Rotary Union Vacuum Extraction Seal Wear
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional rotary unions used in machine tool spindles for cooling and chip extraction suffer from premature wear at the drain port seal, leading to frequent replacements due to coolant leakage, which compromises their reliability and robustness.
Innovation Solution
A rotary union design that utilizes a piston and shaft with pressurized fluid actuation to position seals for coolant flow, eliminating the need for a mechanical seal at the drain port by using a vacuum to evacuate leaked coolant through a dedicated port, thereby reducing wear and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical seal is used at the drain port to prevent coolant leakage, then coolant flow control is improved, but the seal experiences premature wear requiring frequent replacements
Solution Approach 1:
The patent removes the mechanical seal from the drain port location entirely. Instead of trying to seal the drain port, the system extracts the sealing function by allowing the piston to directly contact the shaft and use vacuum extraction to remove coolant, eliminating the high-wear seal component that caused premature failure.
Solution Approach 2:
The patent replaces the mechanical seal system with a vacuum extraction system. Instead of using mechanical contact seals to prevent leakage, the system uses vacuum pressure differential to extract coolant through the drain port, eliminating mechanical wear at the seal interface.
2Reliability
If a seal is placed at the drain port to prevent coolant leakage, then coolant containment is improved, but the complexity of the rotary union increases due to additional sealing components
Solution Approach 1:
The patent extracts the seal from the drain port configuration entirely. The sealing function is achieved through the piston-shaft contact interface and vacuum extraction mechanism, eliminating the need for separate drain port seal components and reducing overall device complexity.
3Manufacturing precision
If pressurized fluid is used to actuate the piston for coolant flow control, then coolant delivery precision is improved, but energy consumption increases
Solution Approach 1:
The system uses the existing pressurized coolant flow itself to actuate the piston through pressure differential. The coolant pressure that would otherwise be wasted or lost controls the piston movement, creating a self-regulating system that improves flow control precision without requiring additional external energy input.
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 solution effectively evacuates coolant without a high-wear seal, improving the rotary union's reliability and robustness by eliminating the need for frequent replacements and maintaining effective coolant flow during high-speed machining operations.
Implementation Method 1
A first port arranged in the proximal portion of the housing is in fluid communication with a cavity formed between the housing and the piston and is configured to deliver a pressurized fluid into the cavity to actuate the piston from the first position to the second position
Implementation Method 2
A second port is arranged in the distal portion of the housing and is in fluid communication with the chamber. The second port is configured to apply a vacuum to the chamber to evacuate coolant fluid leaked into the chamber from the interface between the first fluid passage of the piston and the second fluid passage of the shaft
Data Source
AI summary
A rotary union including a housing, a piston, and a shaft is provided. The piston has a first fluid passage therethrough and is configured to slide axially between a first position and a second position. The shaft has a second fluid passage therethrough and is configured to rotate. A first port is arranged in the housing and is in fluid communication with a cavity formed between the housing and the piston. The first port is configured to deliver a pressurized fluid into the cavity to actuate the piston from the first position to the second position. A chamber is formed in the housing and surrounds an interface between the first and second fluid passages. A second port arranged in the housing is in fluid communication with the chamber. The second port is configured to apply a vacuum to the chamber to evacuate fluid leaked into the chamber from the interface.