Rotary Feed-Through Overload Coupling for Sealed Fluid Release Protection

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Solution Overview

Problem

Rotary joints face issues with uncontrolled fluid release into the environment due to bearing damage, leading to unintended coupling and high moment of inertia, which prevents abrupt braking and results in fluid leakage.

Innovation Solution

Incorporation of a fluid-carrying overload coupling with two coupling halves that decouple at a predetermined limit torque, maintaining a seal and allowing relative rotation, along with a torque detection device to prevent damage and ensure safe operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the rotor is braked abruptly to prevent stator tearing, then the fluid connection can be protected, but the high moment of inertia prevents effective braking

Engineering Contradiction:
Improvefluid connection protectionVSAvoidbraking capability
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The overload coupling is pre-configured with a predetermined limit torque that will cause the connecting element to fail. This preliminary setup ensures that when bearing damage occurs, the coupling automatically decouples at the predetermined torque threshold, preventing stator tearing without requiring active braking control.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The connecting element in the overload coupling is designed as a sacrificial component with a predetermined failure point. When the limit torque is exceeded, this element fails intentionally to protect more critical components (stator and fluid connections). The connecting element can be replaced after failure, while protecting the overall system.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Strength

If the bearing is designed to handle high loads, then the rotor can withstand high torques, but bearing damage still occurs leading to blockage

Engineering Contradiction:
Improvetorque withstand capabilityVSAvoidbearing reliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The overload coupling acts as an intermediary safety mechanism between the rotor and stator. It includes a connecting element with a predetermined failure point that serves as a mediator - when bearing damage causes excessive torque, this intermediary element fails first, preventing direct damage to the stator and fluid connections.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The overload coupling provides beforehand cushioning by being pre-configured with a predetermined limit torque. This creates a safety buffer that activates before catastrophic failure can occur. The connecting element is designed to fail at a specific torque threshold, cushioning the system against higher torques that would cause stator damage.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Productivity

If the rotor and stator are torsionally coupled, then power transmission is efficient, but bearing damage causes unintended coupling and fluid leakage

Engineering Contradiction:
Improvepower transmission efficiencyVSAvoidfluid leakage
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The coupling between rotor and stator is made dynamic rather than permanently fixed. The overload coupling allows normal torsional coupling for power transmission, but automatically decouples when the predetermined torque limit is exceeded. This dynamic behavior enables efficient power transmission during normal operation while preventing fluid leakage when bearing damage occurs.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3828431B1Rotary feed-through
Publication Date: 2022.06.08 CHRISTIAN MAIER GMBH & CO KG
  • EP3828431B1 patent drawingFigure 1~2
  • EP3828431B1 patent drawingFigure 3~4

AI summary

The invention relates to a rotary feedthrough with a stator and a rotor rotatable about an axis of rotation, which is mounted in or on the stator by means of at least one bearing; wherein at least one fluid connection is provided at least on the stator and at least one fluid channel extends through the stator and the rotor in a sealed manner against an environment.The rotary feedthrough according to the invention is characterized in that a fluid-carrying overload coupling is provided in the rotor, which has two coupling halves that are rigidly coupled to each other when a torque below a predetermined limit torque is applied and are decoupled from each other when a torque equal to or greater than the predetermined limit torque is applied, wherein the overload coupling seals the fluid channel from the environment in the coupled and decoupled state of the coupling halves, forms it section by section, and in the decoupled state the two coupling halves are mounted relative to each other so as to be rotatable about the axis of rotation.