Dynamic Balancing 1

[NIHsyndroam]

New dynamic wheel balancing algorithms are changing the tire balancing service industry in big ways. It has been determined that traditional dynamic balancing although not incorrect, has been proven to be significantly wasting time and balancing materials.

The new algorithms are very simple and easy to apply. Instead of treating both static (gm mm) and couple forces (gm mm mm) with the same priority, each is treated independently and a very low couple force magnitude is intentionally left in the wheel when it is balanced wheel. The small couple force has no significance on tire wear or vehicle ride quality and translates to a huge amount of weight not used during the spin balance. Remaining couple weight not used is displayed on a traditional wheel balancer are always revealed as equal in size (assuming the radius of each weight is the same, vectored 180 degrees apart and separated by a distance from each other). The weight saved has no effect on static force being optimized. The small residual couple force remaining also allows for static imbalance optimization and single weight placement on a two-plane balance almost 50% of the time. Some perfected, copied and 'rag-tag examples' of this new dynamic balancing methodology come under various names like SmartWeight, Econobalance, InteliCorrect, etc.

With the common changes in today's wheels to flangeless correction weight positions inside the wheel, the tire companies, tier 1 suppliers and vehicle manufacturers adopt this new balancing methodology they would also benefit by significantly reducing correction weight use. Furthermore, when the total weight used to dynamic balance is used as a tool to measure uniformity, this new methodology reflects more positively on the components, reducing rejects.

Millions of dollars, thousands of tires and tons of material are being wasted when traditionally performing a dynamic balance static and couple forces. Maybe someday the OE will also impliment the change.

What is absolutely amazing is that there seems to be no prior art using this methodology. We are looking for examples of this balancing method being used in any industry that dynamically balances and so far have found none....atleast within the automotive sector. Does anyone have any examples of prior art in automotive or any other industry?

 

[GregLocock]

Interesting idea, but I'd need to see hard numbers, steering wheel sensitivity to unbalance couple is greater than the sensitivity to the static balance.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[CapriRacer]

I think this is one of those uniquely tire related things. The basic premise is that lateral forces play less of a role in vibration generation than radial forces.

So, Greg, I think your premise is wrong. Steering wheel sensitivity seems to be more attached to radial forces, but the problem is that dynamic couple is not expressed in the same units as imbalance, so it's like comparing apples and oranges.

Another way to look at this is that dynamic couple should have a different tolerance level than static imbalance. Right now they don't.

 

[NIHsyndroam]

CR....Exactly, but we dont think this is limited to tires. This could apply to many rotating objects balanced in gm mm and gm mm mm. A plant engineer from DuPont saw this and indicated he could use the same residual couple calcs and more efficiently balance rotating drums in the Nylon plants. 30 ton drums were dynamically balanced with 100lb weights in two seperate weight planes....which took three weeks to place. The key is to optimize the total elimination of static force and radial related issues and then reduce the couple force to small amounts that translate to unmeasureable magnitudes yet huge weight savings. That steering wheel shimmy is almost never couple force.

 

[NIHsyndroam]

This is Taguchi dynamic balancing....Dynamic balancing by static and couple force reduction instead of fixed two-plane weight elimination is the novelty thats in everyones face but has been ignored....or atleast not implimented until now....so by using absolute static gm mm and couple gm mm mm would this not be worthy of an SAE Paper? Think of the unecessary waste that could be saved and the reduction in headaches by standardizing a dynamic balancing calculation.Any takers?

 

[CapriRacer]

A couple of thoughts:

The origination of the first posting is from Hunter Engineering which makes a Road Force machine called the GSP9700.

Let's face it - balancing tires (and rims) involves discreet increments of weight addition, so there is always some residual imbalance. The whole point of the new algorithm is to reduce the amount of weight addition by allowing larger residual imbalance in the dynamic couple. This may or may not be applicable to other balancing scenarios.