Hydraulic Clamp Ring Hub Joint for High-Torque Shaft Interference
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Solution Overview
Problem
Current low moment hub joint assemblies for turbomachinery suffer from limited interference limits between the hub and shaft, leading to potential damage during assembly and disassembly, which compromises machine capacity and reliability.
Innovation Solution
A hub joint assembly comprising a coupling hub and a clamp ring with a conically-shaped bore and passage, utilizing hydraulic fluid to incrementally increase interference pressure between the hub and shaft, preventing adhesion and allowing for higher torque friction fit connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If hydraulic interference fit is used to connect hub and shaft, then torque transmission capability is improved, but interference limit is restricted to 0.002-0.003 inch/(inch of outer diameter of hub) due to adhesion during assembly and disassembly
Solution Approach 1:
A split clamp ring is introduced as an intermediary component between the hub and shaft. The clamp ring applies radial compression force to the hub, which then transfers the interference fit to the shaft. This mediator allows the hub-shaft connection to achieve higher interference levels (0.004-0.006 inch/(inch of outer diameter of hub)) without the adhesion problems that would occur with direct hub-shaft contact, as the clamp ring distributes and controls the assembly forces.
Solution Approach 2:
The clamp ring is designed as a split ring with gaps, allowing it to be assembled around the hub and then uniformly compressed using hydraulic actuators. This segmentation enables controlled application of radial compression force, ensuring even distribution of interference pressure around the hub circumference, and allowing incremental adjustment of the interference fit level beyond traditional limits.
2Power
If higher interference is applied to increase torque capacity, then power density is improved, but surface damage and stuck parts occur during assembly and disassembly
Solution Approach 1:
The clamp ring serves as a protective intermediary that bears the high assembly and disassembly forces, preventing these forces from directly damaging the shaft surface. The clamp ring can be replaced if damaged, while the expensive shaft remains intact. This allows application of higher interference forces (achieving 0.004-0.006 inch/(inch of outer diameter of hub)) that would otherwise cause surface damage, thereby enabling higher torque capacity without compromising the shaft.
Solution Approach 2:
The clamp ring is positioned beforehand to distribute and cushion the high contact pressures that occur during assembly and operation. By pre-positioning this protective element, the system can withstand the harmful forces of high-interference assembly and disassembly without transmitting damaging peak loads to the shaft surface, thus preventing adhesion and surface damage while maintaining high torque capacity.
3Productivity
If interference limit is increased to improve machine capacity, then torque friction fit connection is enhanced, but adhesion during assembly and disassembly leads to stuck parts
Solution Approach 1:
The clamp ring acts as a mediator that decouples the hub from direct contact with the shaft during assembly and disassembly operations. When the clamp ring is compressed hydraulically, it applies uniform radial force to the hub, which then engages the shaft with controlled interference. During disassembly, the clamp ring can be released and removed first, freeing the hub without requiring direct manipulation of the stuck hub-shaft interface, thus greatly easing assembly and disassembly operations while maintaining high machine capacity.
Solution Approach 2:
The clamp ring system transitions from an uncompressed state (easy assembly) to a compressed state (high torque transmission) and back again (easy disassembly). The hydraulic actuators enable dynamic adjustment of the clamp ring compression, allowing the system to be in a low-force state during assembly/disassembly operations and a high-force state during operation, thus resolving the contradiction between ease of operation and machine capacity.
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 enhances the interference limit between the hub and shaft, reducing damage during assembly, improving machine capacity and reliability by allowing higher torque transmission without surface damage, and maintaining low radial strain on the shaft.
Implementation Method 1
A hub joint assembly comprising a coupling hub and a clamp ring with a conically-shaped bore and passage, utilizing hydraulic fluid to incrementally increase interference pressure between the hub and shaft, preventing adhesion and allowing for higher torque friction fit connections.
Implementation Method 2
The clamp ring includes a bore having an inner surface and an outer surface. The inner surface of the clamp ring may be conically-shaped and configured to mate with the outer surface of the coupling hub to form an interface.
Data Source
AI summary
A hub joint assembly for frictionally connecting a shaft to a connector includes a coupling hub including a collar portion and a flange portion. The collar portion includes a bore having an inner surface that is configured to be positioned adjacent to the outer surface of the shaft. The collar portion further includes an outer surface that may be conical. The flange portion extends from the collar portion and is configured to be coupled with the connector. The hub joint assembly further includes a clamp ring including a bore having an inner surface. The inner surface may be conical and configured to mate with the outer surface of the coupling hub. A passage is defined in the clamp ring and extends from an outer surface of the clamp ring to the inner surface of the clamp ring.