Gear Pump Bushing Ring Sealing for Rubber Extrusion

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Solution Overview

Problem

Existing gear pump devices for rubber extrusion require frequent maintenance due to rubber scorch at the support-shaft portion, which can lead to early failure of the drive system, especially when torque increases.

Innovation Solution

A gear pump device with a bushing ring that includes a bearing and a sealing means, featuring a rubber elastic sealing ring with a ]-shaped cross section, which is inserted in the gear-housing bore to rotatably support and seal the support-shaft portion, preventing rubber scorch and reducing torque.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ceramic cylindrical bushing is used to support the gear shaft, then the gear pump can operate for some time, but rubber scorch occurs at the support-shaft portion requiring frequent maintenance every 2-3 months

Engineering Contradiction:
Improvemaintenance intervalVSAvoidrubber scorch
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The support structure is segmented into multiple functional components: a bushing ring with bearing-retaining groove for rotational support, and a separate sealing-means-retaining groove for sealing. This segmentation allows each component to optimize its specific function - the bearing handles rotation while the sealing ring prevents rubber scorch, thereby extending maintenance intervals

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A sealing ring made of rubber elastic body is introduced as an intermediary element between the support-shaft portion and the bushing ring. This sealing ring mediates by preventing direct contact and scorch between the rubber and the support structure, while still allowing the gear to rotate smoothly through the bearing, thus eliminating rubber scorch without compromising operation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If rubber flows through the gap between the bushing and support-shaft portion to reduce scorch, then some scorch prevention is achieved, but maintenance is still required regularly and scorch occurs early with certain rubber types

Engineering Contradiction:
Improverubber scorchVSAvoidmaintenance interval
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The sealing ring is designed as a replaceable, cost-effective component that can be easily replaced when worn. This allows the main bearing structure to remain in use for extended periods while only the consumable sealing ring needs periodic replacement, effectively extending maintenance intervals at low cost

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

Solution Approach 2:

The sealing ring is made from a rubber elastic body with specific material properties that allow it to maintain effective sealing under varying operating conditions. The elastic properties enable the sealing ring to adapt to thermal expansion and wear, maintaining its sealing function throughout the maintenance interval

Inventive Principle:
Principle #35Parameter changes

3Power

If the gear pump operates with increased torque due to rubber scorch, then the drive system may fail, but continuing operation risks catastrophic failure

Engineering Contradiction:
ImprovetorqueVSAvoiddrive system failure
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The bearing incorporated in the bushing ring provides beforehand cushioning by supporting the gear shaft rotation smoothly and reducing friction before excessive torque can develop. This preventive bearing support cushions against the development of harmful torque that would otherwise lead to drive system failure

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

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 solution effectively prevents rubber scorch for a long term, prolonging maintenance intervals and reducing the risk of drive system failure by ensuring reliable sealing and low-torque operation.

Implementation Method 1

the bushing ring has a bearing and a sealing means built-in, the bearing rotatably supporting the support-shaft portion

Methodology Applied
Scientific EffectBall Bearing: Ball Bearing

Implementation Method 2

the sealing means includes a sealing ring which is formed from a rubber elastic body

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3364034B1Gear pump device for rubber extrusion
Publication Date: 2023.05.10 SUMITOMO RUBBER INDUSTRIES LTD
  • EP3364034B1 patent drawingFigure 1
  • EP3364034B1 patent drawingFigure 2
  • EP3364034B1 patent drawingFigure 3

AI summary

In a gear pump device for rubber extrusion, prolongation of the maintenance intervals is intended by preventing rubber scorch occurring at the gear support-shaft portion. It has a bushing ring 5 inserted in a gear-housing bore 3 of a housing 4. The bushing ring 5 rotatably supports a support-shaft portion 7 of a gear 2 accommodated in the gear-housing bore 3. The bushing ring 5 has a bearing 15 and a sealing means 16 built-in. The sealing means 16 includes a seal ring 22 of which cross section is ]-shaped and which has a first lip portion 22i contacting with the outer peripheral surface of the support-shaft portion 7, a second lip portion 22o disposed outside thereof in the radial direction, and a side wall portion 22m connecting between outer ends in the axial direction, of the first and second lip portions 22i, 22o.