Rotatable Shaft Fluid Duct for Tyre Pressure Management

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Solution Overview

Problem

Existing air supply arrangements for vehicle tyres, particularly in steerable axles of agricultural machines, face challenges such as structural instability, space constraints, and corrosion due to offset fluid ducts, which impair the axle's stability and steering geometry.

Innovation Solution

A rotatable shaft with a single bore housing a fluid duct divided into two axial chambers, where one chamber carries pressurized air for inflation and the other for deflation, with rotary passages extending perpendicularly from the duct to the axle housing, maintaining structural integrity and balance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If two separate ducts are used for tyre inflation and deflation, then both functions can be provided, but the axle shaft stability is considerably impaired due to the ducts being offset from the rotational axis

Engineering Contradiction:
Improvetyre inflation and deflation functionalityVSAvoidaxle shaft stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent combines two separate fluid ducts into a single integrated duct structure with two separate fluid passages. This merging approach maintains the dual functionality of tyre inflation and deflation while eliminating the stability issues caused by offset ducts, as both passages are contained within a single centrally-mounted duct body.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single duct is segmented into two separate fluid passages within its structure. This segmentation allows independent routing of inflation and deflation fluid streams through distinct internal channels, maintaining functional separation while achieving external consolidation for improved structural stability.

Inventive Principle:
Principle #1Segmentation

2Reliability

If a sealing assembly is positioned between the two bearings of the axle shaft, then sealing is provided, but a substantial amount of space is required which is not available in steerable front axles

Engineering Contradiction:
Improvesealing functionVSAvoidspace between bearings
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The sealing assembly is nested within the single duct structure itself, rather than requiring separate space between bearings. The sealing elements are integrated into the duct's internal architecture, allowing compact packaging that fits within the limited space of steerable front axle assemblies.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Adaptability or versatility

If ducts are drilled offset from the rotational axis in the axle shaft, then fluid can be conveyed, but the ducts impair the stability of the axle shaft and are susceptible to corrosion

Engineering Contradiction:
Improvefluid conveyance capabilityVSAvoidcorrosion susceptibility
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

Both fluid passages are merged into a single centrally-mounted duct body, eliminating the need for offset drilling. This central positioning removes the corrosive fluid pathways from the critical structural zones of the axle shaft, preventing corrosion while maintaining fluid conveyance functionality.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of manufacture

If axial rotary passages are used for air transmission, then no changes to axle components are required, but additional space is required outside the axle housing

Engineering Contradiction:
Improveretrofit capabilityVSAvoidspace outside axle housing
Core Design Contradiction:
Ease of manufactureVSArea of stationary object

Solution Approach 1:

The invention transitions from axial air transmission requiring external space to radial rotary passages that utilize the internal dimensional space within the axle housing. By changing the transmission dimension from axial to radial, the system eliminates the need for external mounting space while maintaining air conveyance capability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP2768683B1Rotatable shaft comprising a fluid duct
Publication Date: 2015.12.16 AGCO INT GMBH
  • EP2768683B1 patent drawingFigure 1
  • EP2768683B1 patent drawingFigure 2
  • EP2768683B1 patent drawingFigure 3

AI summary

A rotatable shaft comprising a fluid duct wherein the fluid duct extends through a single bore in the shaft and the fluid duct is provided with at least two chambers extending axially along the bore.