Electric Torque-Limiting Clutch With Self-Powered Fluid Pressure Reset

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Solution Overview

Problem

Existing torque limiting clutches for rotary shafts face issues with fluid leakage, environmental concerns, inability to handle short torque spikes, pressure variability with temperature, and risk of seizing damage due to low-hardness weldable materials.

Innovation Solution

A clutch design featuring a control means with a pump and generator to manage fluid pressure, a cam wheel trigger device for precise disengagement, and a gasket seal instead of welding to minimize leakage and allow the use of hard metal materials, enabling efficient torque control and quick reset.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the thin-walled sleeve is welded to the housing to limit leakage, then leakage is reduced, but the weldable material has low hardness leading to risk of seizing damage

Engineering Contradiction:
Improveleakage preventionVSAvoidmaterial hardness
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The clutch is divided into separate components: the thin-walled sleeve is no longer welded to the housing but is instead held in place by a retaining ring. This segmentation allows the sleeve to be made of hard metal material without compromising the sealing integrity, as the retaining ring provides mechanical retention while the gasket seal prevents leakage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A gasket seal is introduced as an intermediary element between the thin-walled sleeve and the housing to prevent leakage. This gasket allows the use of hard metal materials for the sleeve while maintaining sealing effectiveness, eliminating the need to weld low-hardness materials to the housing.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the disengaging mechanism is tripped upon relative angular movement, then torque limiting is achieved, but the pressurized fluid leaks out causing soiling and environmental problems

Engineering Contradiction:
Improvetorque limiting functionVSAvoidfluid leakage and soiling
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

Instead of allowing the pressurized fluid to leak out into the environment when the disengaging mechanism is tripped, the system recovers the fluid by channeling it back into the chamber. This closed-loop approach maintains torque limiting functionality while preventing environmental contamination and soiling.

Inventive Principle:
Principle #34Discarding and recovering

3Force

If larger sealed surfaces are used in the construction, then the clutch can handle larger torques, but leakage increases making the clutch useless

Engineering Contradiction:
Improvetorque capacityVSAvoidfluid leakage
Core Design Contradiction:
ForceVSLoss of substance

Solution Approach 1:

A gasket seal is introduced as an intermediary sealing element that enables the use of larger sealed surfaces without proportionally increasing leakage. The gasket provides effective sealing across larger areas, allowing the clutch to handle larger torques while maintaining fluid containment.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Weight of moving object

If the clutch is designed with small dimensions and low weight, then compactness is achieved, but the capacity to quickly reset after disengagement is compromised

Engineering Contradiction:
Improveclutch weightVSAvoidreset speed
Core Design Contradiction:
Weight of moving objectVSProductivity

Solution Approach 1:

The reset mechanism is enhanced by incorporating a spring-loaded system that automatically and quickly resets the disengaging mechanism after torque overload. This mechanical substitution enables rapid reset functionality in a compact, lightweight design without compromising productivity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 design minimizes fluid leakage, allows for precise torque control, reduces environmental impact, and prevents seizing damage by using hard metal components, while maintaining compactness and efficiency.

Implementation Method 1

a thin-walled sleeve (130) forming an axially extended thin wall of the annular chamber (110), which chamber (110) is arranged to be supplied with pressurized fluid for substantially elastic deformation of the sleeve (130)

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

a control means (160) with a pump (161), in turn arranged to pump fluid to the chamber (110) so as to achieve said pressure therein

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 3

a generator means (163) arranged to harvest electric energy from the rotation of the shaft (10), in that the generator means (163) is arranged to power the control means (160)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3833883B1Torque-limiting clutch comprising an electric control system
Publication Date: 2023.06.07 C FALK REMOTE CONTROL AB
  • EP3833883B1 patent drawingFigure 1~2
  • EP3833883B1 patent drawingFigure 3a~4
  • EP3833883B1 patent drawingFigure 3b

AI summary

Clutch (100) for a rotary shaft (10), said clutch (100) comprising an annular pressure chamber (110) with a sleeve surface (131 ) engaging a surface (11 ) to drivingly connected the shaft (10) to the clutch (100), further comprising a trigger device (140) and a channel system (150) activatable by said trigger device (140) upon a relative angular movement between the shaft (10) and the chamber (110) to release the shaft (10) from the housing (120). The invention is characterised in that the clutch (100) further comprises a control means (160), arranged to receive said fluid through the channel system (150) from the chamber (110), and comprising a pump (161 ) for pumping fluid to the chamber (110). The control means (160) is fixedly arranged to the housing (120), rotating with the shaft (10). The clutch (100) comprises a generator means (163), harvesting electric energy from the rotation of the shaft (10) and powering the control means (160).