Co-Moulded Washing Machine Hose for Seal Seat Stability

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Solution Overview

Problem

Current co-moulding processes for washing machine tubes face challenges due to high injection pressures and temperatures, leading to irreversible deformations that compromise the sealing capacity of the seal, making it critical to prevent such deformations and ensure reliable watertight sealing.

Innovation Solution

A co-mouldable tube design with a plastic housing sleeve featuring an annular rim for a sealing element, an annular frontal groove for a cylindrical stiffening body, and a spacer with a box-type structure to maintain the seat's geometry and prevent deformation, along with radial antirotational teeth for stability, which are co-moulded with rolling bearings and a spacer to simplify and enhance the assembly process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If co-moulding is performed with high injection pressure and temperature to reduce production time, then productivity increases, but the sealing seat undergoes irreversible deformation compromising sealing reliability

Engineering Contradiction:
Improveproduction timeVSAvoidsealing capacity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The sealing seat is pre-formed with reinforced geometry during the co-moulding process, creating a structurally stronger seat before the sealing element is installed. This preliminary reinforcement allows the seat to withstand high injection pressures without deforming, enabling both high productivity and maintained sealing reliability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The design modifies the geometric parameters of the sealing seat by adding a reinforcing rib structure that increases its stiffness and resistance to deformation. This structural parameter change allows the seat to maintain its dimensional stability under high injection pressure conditions while still enabling efficient co-moulding production

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If co-moulding is performed with high injection pressure to simplify assembly, then ease of manufacture improves, but manufacturing precision of the sealing seat deteriorates

Engineering Contradiction:
Improveassembly simplificationVSAvoidseat geometry accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The sealing seat geometry is pre-designed with built-in reinforcement features during the co-moulding process, preparing the structure in advance to resist deformation under injection pressure. This preliminary structural preparation maintains manufacturing precision while enabling the simplified integrated manufacturing process

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The sealing seat is designed as a composite structure combining the plastic housing material with integrated reinforcing ribs, creating a multi-functional component that maintains geometric precision under high injection pressure while still being manufactured through the simplified co-moulding process

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2372008B1A hose co-mouldable with washing machine tubs
Publication Date: 2016.08.24 AB SKF SKF PATENT DEPARTMENT
  • EP2372008B1 patent drawingFigure 1~2

AI summary

A hose (10), co-mouldable with washing machine tubs (11), comprises - two rolling bearings (20, 30) arranged along an axis (a) of rotation of a washing machine drum; - a spacer (40) interposed between the two bearings (20, 30); and - a housing sleeve (50) preferably made of a plastic material and by co-moulding around the two bearings (20, 30) and the spacer (40). The housing sleeve (50) has an annular rim (51) which projects axially from a first one (30) of the two bearings (20, 30) in a position that is coaxial with the axis (a) of rotation and defines a seat (52) for a sealing element (53).