roller gearing and transmission technology pál bogár sincroll - drive technologies ltd london

www.sincroll.com • +44 (0) 781 666 7711 • [email protected]

Roller Gearing and Transmission Technology

Pál Bogár

sincroll - drive technologies ltd

London


Agenda - 45mins

• The Innovative Idea - what new do we do

• Realisation of the Idea - how do we do it

• Design Examples - what variety can we do

• Concept Prototype Tests - facts and proofs so far

• Benefits and Advantages - why should it be used

• Potential Applications - where could it be used

• Running Application Projects - who got interested so far

• The Sincroll Company - our business, skills and facilities


The Innovative Idea

Brand new technology - 8 months in the market

Trivial problem – non-trivial solution

• Rollers connect the wheels– wheels do not connect directly – there are no “teeth”

• Rollers roll along the grooves on both wheels simultaneously– rigid coupling between the wheels

• Rollers do pure rolling motion without sliding– ensured by the shape of the

grooves


• Forces transmit via “single” contact points between rollers and grooves– lines of contact points determine

the lines of the grooves and the shape of the wheels

– cross-sectional shape of the grooves is irrelevant

– lines of grooves are key to ensure proper forces for pure rolling motion

• Hertzian stress is well contained– curvatures of rollers and grooves

are similar near the contact point

Realisation of the Idea

• More like a ball screw than a conventional toothed-wheel gear


Realisation of the Idea (cont’d)

Complex physics

G: roller (ball)

P1, P2: contact points between the balls and the wheels

gp: path travelled by the ball’s centre when in coupling

g1, g2: paths travelled by the contact points

u, v: various velocity vectors

1, 2: angular velocity vectors of the two wheels


The technology is …

• universally applicable to any gearing problem

– any shaft angles– crossing or non-crossing axes– internal or external coupling– planetary systems and worm gears– linear drives and gear racks

• highly flexible and rich in design– for any given gearing problem,

provides a variety of solutions – highly optimisable and customisable

• very different from conventional – it is more like a generalised ball

screw or roller bearing

Design Examples


non-intersecting axesaxes angle = 90o

gearing ratio = 1:1ball diameter = 4mmcontact factor = 8

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intersecting axesaxes angle = 90o


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parallel axesaxes angle = 0o


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parallel axesdirection of rotation = oppositegearing ratio = 23:25ball diameter = 4mmcontact factor = 19

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non-intersecting axesaxes angle = 45o


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parallel axes gear rackaxes angle = 45o

gearing ratio = n/aball diameter = 4mmcontact factor = 16

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perpendicular axes gear rackaxes angle = 90o

gearing ratio = n/aball diameter = 4mmcontact factor = 10

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internal coupling non-intersecting axesaxes angle = 45o


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micro-rollers non-intersecting axesaxes angle = 45o


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Concept Prototype Tests

• The prototype tested was the 1:10 non-intersecting axes, 45o setup• Made of steel with nitriding finish of grooves surfaces• Test lab at the Budapest University of Technology• Tests supervised by the Department of Machine and Product Design

• Tests performed: All this was done: – Basic checks of operations - With and without back-lash– Kinematics and noise checks - For both directions of rotation– Static power efficiency - For both directions of load– Dynamic power efficiency - For various angular velocities– Movement precision – Reliability


non-intersecting axes T E S T P R O T O T Y P Eaxes angle = 45o


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www.sincroll.com • +44 (0) 781 666 7711 • [email protected] Page 18




The Test Rig


Test Data for Movement Precision


Summary of Test Results

• Basic operations, kinematics, noise and reliability – no particular issues, performance was quite good in all respect

• All tests were insensitive (in terms of statistical significance) to– changing direction of rotation– changing the direction of the load– and whether the back-lash was eliminated or not

• Static efficiency at least 98% - this was independent of – roller recycling device being in place or not – back-lash has been eliminated or not (surprise!)

• Dynamic efficiency at least 94%– groove surfaces were sub-optimal as a result of nitriding– we will re-test again soon with polished groove finish and improved roller

recycling device


Summary of Test Results (cont’d)

• Movement precision showed a periodic structure where the periodicity was the same as the period of revolutions of the larger wheel in the gear. This shows there was a manufacturing error in the larger wheel.

– the error was about +/- 0.2 degrees – looks like a normal amount of inaccuracy and should not be a cause for alarm

– we want to retest with a higher precision electronics to see if anything else besides the larger wheel has an effect on precision


parallel axes A L U M I N I U M P R O T O T Y P Eaxes angle = 0o ( n o t t e s t e d )gearing ratio = 26:23ball diameter = 4mmcontact factor = 8

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parallel axes A L U M I N I U M P R O T O T Y P Eaxes angle = 0o ( n o t t e s t e d )gearing ratio = 26:23ball diameter = 4mmcontact factor = 8


Benefits and Advantages

• Power efficiency close to 100% – due to pure rolling motion done by the rollers – sliding friction is practically eliminated

• Contact factor up to 20 or more– load distributes over many rollers

• Back-lash eliminated– easy to eliminate back-lash by forcing the wheels together– efficiency loss is in-significant

… and implications of these


Implied Advantages (Expected)

High power efficiency

• No sliding friction• Lower energy losses• Lower starting torque• Smaller motor needed• Friendlier to the

environment – a green technology

• Lower operating costs• Reduced heating up• Reduced abrasion• Less cooling and

lubrication needed• Less wear and

deterioration• Longer lifetime• Less vibration and noise

High contactor factor

• Smaller size• Higher power density• Smoother and steadier

movements• Precise movements• Lower noise• Greater reliability

No back-lash

• Precise movements• Less vibrations and

resonances• Longer lifetime


• High-power drives– due to low operating costs, small

size and good reliability

• All vehicles– due especially to high efficiency,

high power density, special shape and long lifetime

• Material handling machines– due especially to smaller

actuating torque and reliability

• Machine tools– due to eliminated back-lash– alternative to ball-screw drives

• Wind power generators– due to high energy efficiency,

high gear-up ratio, no back-lash

• Standard gear families– especially worm gears and bevel

gears due to high efficiency and compact size, respectively

Potential Applications

Applicable in all areas of mechanical gearing and power transmission Including any / high or low:

o torque o ratio o precision o rpm o size

For example:


• Wind turbines– Yaw and pitch drives– Main gearbox

• Machine tools– Turning tables

• Aviation– Flight control drives/actuators

• General industrial– Worm gears– Parallel-shaft gears– Planetary gears– Right-angle “bevel” gears– Linear actuators– Precision drives– Plastic gears– Miniature gears

• Car transmission, 5 fwd+1 back– Parallel axes, complex setup

• Car rear axle hypoid gearsRight-angle

– Intersecting axes– Non-intersecting axes– Twin-wheel

• Car parts– Window lifter– Engine starter

• Truck rear axle hypoid gears– Same as car hypoid gears

• Railway traction drives– Same as car hypoid gears– Also parallel axes

Running Application Projects


• Our primary business of the new roller gear technology

• research and development• commercialisation and transfer

• Our design and development skills twenty years of experience in

• scientific research • computer aided design and simulations• applications design and development, evaluation and testing

• Our management skills twenty years of experience in

• scientific research• corporate management• entrepreneurial and start-up management

The Sincroll Company


• Access to machining facilities– manufacture of high-quality prototypes – build test equipment and perform basic tests– produce on a relatively small scale, pilot runs

• Access to suppliers– local market knowledge– supplier contacts, networks and relationships – twenty years of experience, track record

• Wide range of services– basic R&D, theoretical and experimental work– specifications and analysis, advisory and design– prototype and applications manufacture and testing– production advisory and outsourcing– technology licensing

The Sincroll Company (cont’d)

roller gearing and transmission technology pál bogár sincroll - drive technologies ltd london

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