Seamless Rotary Guidance System: Bishop-Wisecarver 1-Trak Part I

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Motion Without Limits ®

Introducing PRT2 1-Trak: Part I of III

A Seamless Ring and Track Guided Motion System



OUTLINE OF OVERVIEW — PART I OF III

Original PRT2 Systems

New 1-Trak Systems

Any Shape, Any Size

Four Bearing Carriage

Three Bearing Carriage

Track Geometry

Rectangular Section Track System

Contact Information



ORIGINAL PRT2 TRACK SYSTEMS

The PRT2 precision ring and track offering is one of BWC’s most popular motion guidance solutions

Includes broad range of sizes and component types

Market leading products

However, in some instances the traditional PRT2 offering did not meet certain specifications



NEW! PRT2 1-TRAK

1-Trak extends the capability of PRT2

Patent pending design with three key innovations:Create almost any 2D shape of track in one piece(within the maximum size limits and minimum bend radii)

Three-bearing geometry allows a carriage to run around any 2D shape of track

Available with or without gear drive



WE CAN MAKE ANY SHAPE

A new manufacturing method for creating rings has been developed since 2011:

Parts are made using special steel, are precision machined, and surface hardened

This route gives high surface hardness and very low distortion

Applicable for all sizes (from miniatures to huge HD parts)



ANY SHAPE, ANY SIZE

Ring is much thinner for this diameter than can be manufactured using the traditional approach



Hyperbolic shape

Assembly is Ø4.4 m

Made in smaller pieces and butted together

ANY SHAPE, ANY SIZE



ANY SHAPE, ANY SIZE

Our CAM software provides for the ability to make unusual and complex components

We can create a PRT2 track in one piece



ANY SHAPE, ANY SIZE

Tracks can be made to include an integral base plate

No installation or adjustment

Can be major structural element of machine



ANY OF THESE STYLES ARE POSSIBLE



CREATE ANY SHAPE

The steel has a high tensile strength, more than 900MPa: stronger than a standard 8.8 hex socket screw

This gives indentation resistance beyond the max load capacity of all compatible vee bearings

Surface hardened to > 600HV (~ 55HRC+)Case depth is ~0.2mm

Great wear resistance(proper lubrication is essential for long life)

The finish is precision machined, producing a great running surface



FOUR BEARING CARRIAGE GEOMETRY

Four Bearing Fixed Centre Carriage

The lift-off increases as:

Segment diameter reduces

Track width increases

Bearing separations increase

This limits the proportions of useful track systems



FOUR BEARING CARRIAGE GEOMETRY



THREE BEARING CARRIAGE GEOMETRY




As two bearings on the outside roll around the track, the inside vee bearing will follow a unique path

The 1-Trak approach calculates this unique shape, and machines it accurately into the inside of the track




The width of the track is constantly changed depending upon its bend radius

In this example, dimensions A, B, C, and D are different

A dedicated CAM system automatically creates the track geometry to very high precision




Our manufacturing approach can accurately produce finished components with close tolerances on straightness, flatness, and shape

Within 0.002” flatness in the free state




Carriage uses three off SJ25 bearings: Load capacity << four bearing carriage — center of load capacity is offset

Section based on NS25 (like 25 section PRT2 rings)

Pitch (MP), Yaw (MY), and Roll (MR) moment load capacities are modest compared to FCC25 255




Carriage uses one SJ18 on the inside and two SJ13’s on the outside: the load capacity is broadly symmetrical

Track section and spacing of bearings is wide

Carriage Roll (MR) moment load capacity is high, despite the tight bend radius

Integral base plate is a very strong/stiff structural element




Different sized bearings and an asymmetrical track profile will produce a carriage with even load capacity

The larger bearing is taller, but this does not cause a problem for systems which are hollow in the middle



TRACK GEOMETRY

Virtually any smooth 2D shape can be made into a

1-Trak system, providing that the bearing radii and separation will allow the carriage to go round

Free-form curves are no problem



TRACK GEOMETRY

Tracks can be open or closed shapes



RECTANGULAR SECTION TRACK SYSTEM

1-Track construction can be used to make tracks with a “flat track” floating function for use in parallel mounted systems



RECTANGULAR SECTION TRACK SYSTEM

1-Trak approach gives flexibility to make rectangular section tracks (similar function to PRT2 floating bearings)

Floating bearings can be used with vee profiled 1-TrakRollers will give lower friction, better track life and lower cost

Tracks designed for 4-bearing carriages to operate in parallel with standard PRT2 track systems with FCC carriages are possible



CONTINUED…

Be sure to view part II of III in the 1-Trak overview series for more information on:

Driving By Gears

Available on the Bishop-Wisecarver’s SlideShare: (www.slideshare.net/bishopwisecarver)

http://www.slideshare.net/bishopwisecarver



THANK YOU

Have questions? Please contact…An Applications Engineer at (888) 580.8272

Or email [email protected]

Learn more on our website at www.bwc.com

Date post:	06-Dec-2014
Category:	Technology
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Seamless Rotary Guidance System: Bishop-Wisecarver 1-Trak Part I

Technology