Food Shaft Support Assembly With Labyrinth Inner Seal

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Solution Overview

Problem

Existing support assemblies for movable shafts in the food industry fail to maintain effective sealing under high-pressure and high-temperature water jets, leading to contamination and failure in IPx9k certification tests due to the lifting of sealing lips and inadequate sealing in the axially inner part.

Innovation Solution

A novel support assembly design featuring a modified radially inner ring with a step that extends axially inward to accommodate an additional shield, forming a labyrinth seal with the existing shields, enhancing the axially inner seal and preventing water ingress into the bearing unit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the support assembly uses conventional sealing lips to seal the bearing unit, then the structure is simple and easy to manufacture, but the sealing performance fails under high-pressure and high-temperature water jets

Engineering Contradiction:
Improvesealing performanceVSAvoidsealing structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sealing structure is divided into multiple independent sealing lips (first sealing lip and second sealing lip) arranged in sequence along the axial direction. Each sealing lip independently contacts the shaft to provide sealing, creating a multi-stage sealing system that prevents water ingress under high-pressure conditions while maintaining manufacturability through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single sealing lip design to a multi-dimensional sealing arrangement by positioning sealing lips at different axial locations and orientations. The first sealing lip seals the axially outer side of the bearing unit, while the second sealing lip seals the axially inner side, creating a three-dimensional sealing barrier that effectively blocks high-pressure water jets from multiple angles

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

2Reliability

If the support assembly uses a single shield with sealing lips to protect the bearing unit, then the device complexity is low, but water enters through the axially inner seal under high-pressure jets

Engineering Contradiction:
Improveprotection against water ingressVSAvoidnumber of shielding components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The shielding function is segmented into multiple components: a first shield with a first sealing lip for the axially outer side, and a second shield with a second sealing lip for the axially inner side. This segmentation allows each shield to be optimized for its specific sealing location, preventing water ingress under high-pressure conditions while maintaining reasonable device complexity through functional specialization

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces sealing lips as intermediary elements between the shields and the shaft. These sealing lips act as mediators that directly contact the shaft surface to create effective sealing, while the shields provide structural support and positioning. This intermediary approach enhances protection against water ingress without requiring overly complex shield designs

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4075003B1Support assembly for food applications having an improved inner seal
Publication Date: 2024.03.20 AB SKF SKF PATENT DEPARTMENT
  • EP4075003B1 patent drawingFigure 1
  • EP4075003B1 patent drawingFigure 2

AI summary

Support assembly (1) for movable, rotating or sliding shafts (5), having a bearing unit (30) adapted to receive the movable shaft, a casing (3) and a cover (10) for fluid sealing an opening (11) of an internal seat (4) of the casing (3); the bearing unit (30) having a radially outer ring (31), a radially inner ring (34) and a row of rolling elements (32) between the radially outer ring (31) and the radially inner ring (34); the support assembly (1) also being provided with: - a rear sealing device (50), placed on the opposite side with respect to the cover (10); - a sealing device which is axially internal with respect to the row of rolling bodies (32), comprising a single shield (55) provided with a vulcanized rubber liner having a plurality of sealing lips; the support assembly (1) being characterized in that, from the opposite side with respect to the cover (10), the radially inner ring (34) is provided with a step (35) which extends in an axially inward direction and on which is accommodated a further shield (54), provided with a vulcanized rubber liner having a plurality of sealing lips.