Shaft Balancing Device with Internal Crush Points

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Solution Overview

Problem

Driveshafts made from commodity materials with non-uniform wall thicknesses often result in static imbalances, leading to excessive vibrations and noise in drivetrain assemblies, necessitating the use of balancing weights to counteract these imbalances.

Innovation Solution

A shaft balancing device featuring a plastically deformable, generally flat cylindrical band with crush points and a balancing weight attached to its outer surface, which is inserted into the shaft and secured using a spring force created by deforming the crush points to contact the shaft's inner surface, providing a secure attachment mechanism for the balancing weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If balancing weights are attached to the outside surface of the shaft, then static imbalance is reduced, but the device complexity and manufacturing cost increase

Engineering Contradiction:

Improvestatic balanceVSAvoidattachment mechanism complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The band is inserted inside the shaft, and the balancing weight is attached to the outer surface of the band, creating a nested configuration where the band and weight are contained within the shaft. This eliminates the need for external attachment mechanisms while achieving the balancing function.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

Instead of attaching the balancing weight to the outside surface of the shaft as in conventional approaches, the invention inverts the approach by placing the band with the balancing weight inside the shaft. This inversion simplifies the attachment mechanism while achieving the same balancing effect.

Inventive Principle:

Principle #13The other way round (Inversion)

2Ease of manufacture

If commodity materials with non-uniform wall thickness are used, then manufacturing cost is reduced, but static imbalance increases

Engineering Contradiction:

Improvemanufacturing costVSAvoidstatic balance

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The balancing weight attached to the band inside the shaft acts as a counterweight to compensate for the static imbalance caused by non-uniform wall thickness in the commodity material driveshaft. This allows the use of lower-cost materials while maintaining balance.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The balancing weight is positioned at a specific location on the band inside the shaft to counteract the local imbalance caused by non-uniform wall thickness. This localized compensation allows the use of commodity materials with variations in wall thickness while achieving acceptable balance.

Inventive Principle:

Principle #3Local quality

3Device complexity

If the band is made plastically deformable with crush points, then the attachment mechanism is simplified, but the manufacturing precision requirements increase

Engineering Contradiction:

Improveattachment mechanism complexityVSAvoidcrush point deformation control

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The band is designed to change its physical state from undeformed to plastically deformed at the crush points during installation. This parameter change allows the band to expand radially and secure itself to the shaft, simplifying the attachment mechanism while requiring controlled deformation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The crush points are pre-formed on the band during manufacturing, preparing the band for the deformation process that will occur during installation. This preliminary action ensures that the band will properly expand and secure the balancing weight when the crush points are deformed.

Inventive Principle:

Principle #10Preliminary action

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

Effectively reduces static imbalances in driveshafts, thereby minimizing dynamic imbalances and associated vibrations and noise in drivetrain assemblies, while being cost-effective by utilizing lower-cost materials.

Implementation Method 1

The crush points project radially inward from the inner surface of the band and can be plastically deformed radially outward bringing the two ends of the band in contact

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

creating a spring force which holds the balancing weight to the inner surface of the shaft

Methodology Applied

Scientific EffectSpring force: Spring

Data Source

PatentUS10060505B2Device for securing balancing weights to a shaft

Publication Date: 2018.08.28 DANA AUTOMOTIVE SYST GRP LLC

AI summary

A shaft balancing device for insertion into a shaft including a generally flat cylindrical band having an outer surface, an inner surface and a set of two crush points thereon. A balancing weight is attached to the outer surface of the band between the set of crush points. The device is inserted into the shaft and the crush points are plastically deformed radially outward creating spring force which holds the balancing weight to the inner surface of the shaft. The band has a curved connecting portion between the two crush points having a radius of curvature slightly greater than the curvature of the shaft. The balancing weight has a radius of curvature slightly greater than the radius of curvature of the curved connecting portion and slightly less than the radius of curvature of the shaft.