Liberty Massive Mini10/12/2013
Rex Brown
Team Driven #1730
Lee’s Summit High School
Mentor
For Inspiration and Recognition of Science and Technology
Synchronous Belts (Thanks to Gates Belt for Slides)
Drive Trains (Thanks to Madison Krass & Fred Sayre)
Q&A
Agenda
Gates Rubber Synchronous Belt Drives
FIRST Robotics Applications
FIRST Robotics Competition – 2008/2009
Gates Rubber Synchronous Belts
Benefits for First Robotics Competition
Gates PowerGrip® GT®2 5MM belts are ideally sized for drives and functional applications on a FIRST robot
Lightweight – much lighter than chain and gearing systems for comparable loads
Useful – PowerGrip rubber belt drive systems are ideal not only for drives, but also for linear motion, lifts, game object conveying, positioning, and even for precisely flinging objects
Easy to Work With – aluminum sprockets are easy to machine and belting can be wrapped, cemented, or riveted to structure
Clean – these drives remain clean because oil is not needed and present a complete image of current technology
Quiet – reduced noise as compared with other belt drive technology such as chain and gears
Tooth ProfilesTooth Profiles
PG Timing, Trapezoidal, PG Timing, Trapezoidal, GilmerGilmer
TwinPower TimingTwinPower Timing
(Also available in PowerGrip GT2)(Also available in PowerGrip GT2)
HTDHTD Gates GT, GT2Gates GT, GT2
Gates Synchronous BeltsGates Synchronous Belts
Materials Supplied in 2007Materials Supplied in 2007
Power GT2 Belts
Aluminum HTD Sprockets– Why not GT2 Sprockets
Synchronous Belt DrivesSynchronous Belt Drives
For Comparison Purposes, Let’s give HTD a rated capacity of 1.0 when operating with For Comparison Purposes, Let’s give HTD a rated capacity of 1.0 when operating with HTD sprocketsHTD sprockets
Typical Belt and Sprocket Profile for HTDTypical Belt and Sprocket Profile for HTD
Synchronous Belt DrivesSynchronous Belt DrivesDuring the mid 1990’s, Gates replaced the PowerGrip HTD belt with PowerGrip GT belts, During the mid 1990’s, Gates replaced the PowerGrip HTD belt with PowerGrip GT belts, and continued running with HTD sprockets. and continued running with HTD sprockets.
Typical PowerGrip GT belt in HTD spktTypical PowerGrip GT belt in HTD spkt
Synchronous Belt DrivesSynchronous Belt Drives
PowerGrip GT2 Drive System
Typical PowerGrip GT2 belt and sprocket profile
Application Notes Application Notes
Handling the Belts – Do not bend belts smaller than the diameter of the 15 groove sprocket.
A one time tight bend or crimp will break the belt’s fiberglass tensile member and cause loss of strength and failure of the belt.
Belts can not be joined or spliced by any means other than grooved splice plates with a minimum 6 teeth.
OK! No Way!Drive Alignment - Sprockets must be aligned and shafts
parallel in both planes.
Sprocket Flanges – Provide Flanges either on both sides of one sprocket or one side on the driver and the opposite side on the driven sprocket. All belts drive to one side of the sprocket. You must use flanges.
Guarding & Debris protection – A piece of flat plastic supported in between the belt spans is a simple way to eliminate pinch points and keep debris out of the drive.
Application NotesApplication NotesBelt Tensioning – Tension the belt so that when the drive is under full anticipated load (including shock loads) the belt does not
get slack on one side, or the belt teeth try to climb out of the sprocket grooves. Light load – light pre tension; Heavy load – higher pre-tension. Make sure the mounting structure does not deflect when either tensioning the belt or under operating conditions. If you loose tension, the belt will jump teeth. Keep belt shafts parallel and sprockets in line with each other.
Belt Wrap – Minimum of 6 belt teeth fully in mesh & (60°) belt wrap on the circumference of each sprocket. This will allow a properly tensioned belt to perform at 100% of its load rating. A backside idler can be useful for both tensioning the drive and increasing belt wrap. The idler is used on the slack side of a belt drive. Reversing drive – Idler on either side.
Max “climbout” under load
Too little tension or pulley mounting needs more structure
Product Ratings – Gates belt ratings are set to guarantee long life on industrial applications. For FIRST applications, your load capability is going to be determined by the shaft to sprocket connections, belt wrap, and the ability to pretension the drive so that the belt does not jump teeth. With adequate belt wrap & proper installation tension, you will be surprised by the durability of this product! Load capability of the 09 and 15MM width belts is proportional to their width.
Best advice – One test is worth a 1000 calculations.
Typical 6-Wheel Synchronous Drive
Notes:
•CIM motor primary drive uses 9MM wide belt. Higher torque load on wheel drives uses 15MM wide belt. Front wheel would be 9 or 15 wide depending on loading.
•Rule of Thumb: If using belts for speed reduction, use narrower belts on higher speeds (usually coming from the motor) and wider belts at the lower speeds (powering the wheels)
•Note use of sprocket flanges and belt tensioning points.
•Provide adequate structure to maintain parallel shafts, sprocket alignment, and ability to maintain tension under load.
•Total drive ratio is 7.9 : 1
Telescoping Lift with door motor & 5mm Long Length Belting
Need a reversing drive? PowerGrip Twin Power® belts have teeth on both driving surfaces.
Application Notes1.25” diameter flat rollers with a flange can be used for idlers (either side of the belt.)Make an easy end connection – for 5mm pitch, 9mmwide belting long length belting, make a ferrule from ½ diameter x .035 x 1” Al or Cu tubing. Wrap belting around min. ½” diameter cylinder (to avoid belt cord damage) and insert belt loose ends through ferrule. Crimp the ferrule in a vise. Don’t crimp too tight and you will have a removable connection. Belt Tensioning – note adjustment screws
Robotics Belt Applications
Ball Pitching using opposing belts and a PowerGrip Twin Power belt (teeth on both sides) to reverse rotation. Fast and Accurate!
2 stage, 13:1 ratio positioning drive. Small sprocket on inside of belt span drives a position feedback pot.
Drive DesignDrive DesignDrive DesignDrive Design
Pulley Flanging Requirements– Standard Belts Must Be Restrained On Both Sides– Every Pulley Does Not Require Flanging
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OK OK OK
Drive DesignDrive DesignDrive DesignDrive Design
Pulley Flanging Requirements– Long Belt Spans May Need Additional ConstraintoBelt Spans > 8X The Pulley Diameter May Exhibit Greater Than
Normal Tracking Forces
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D 8 x D
o Idler Pulleys Can Be Flanged And Used To Constrain Belts As Needed
Drive DesignDrive DesignDrive DesignDrive Design
Pulley Flanging Requirements– Shaft Misalignment Results In Belt Tracking ForceoShaft Non-ParallelismoShaft Deflection
– Synchronous Belts Always Track “Down Hill”
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BeltTracking
BeltTracking
Drive DesignDrive DesignDrive DesignDrive Design
Drive Alignment Requirements
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Ideal Alignment
Parallel Misalignment
Angular Misalignment
– 1/4 Maximum Allowable (Angular + Parallel)
– Shaft Parallelism Influences Belt Tracking
– Shaft Parallelism Influences Belt Tensile Loading
Application: Selecting The Correct DriveApplication: Selecting The Correct DriveApplication: Selecting The Correct DriveApplication: Selecting The Correct Drive
Special Characteristics– Belt Tooth Jumping ResistanceoTooth Jumping Generally Begins At The Entry Point Into The
Driven Pulley– Belt Pre-Tension Is Needed To Prevent Tooth Jumping– Large Sprocket Diameters Reduce Tooth Jumping
oDrives With Short Centers Have Greater Tooth Jumping Resistance Than Drives With Long Centers– Short Belts Elongate Less Under Equivalent Loads
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Application: Selecting The Correct DriveApplication: Selecting The Correct DriveApplication: Selecting The Correct DriveApplication: Selecting The Correct Drive
Special Characteristics Cont.– Belt Tooth Jumping Resistance Cont.oMaximize Tooth Jump Resistance By:
– Designing With A Larger Belt Pitch Drive System– Designing With Large Sprocket Diameters– Increasing Belt Installation Tension– Maintaining Rigid / Non Collapsing Center Distance
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NOTES PowerGrip GT2 part numbers are comprised of pitch, pitch length and width For example, 5MR-400-09 signifies 5mm pitch, 400mm pitch length and 9mm width Belt pitch is the distance in millimeters between two adjacent tooth centers as measured on the pitch line of the belt. Belt pitch length is the total length (circumference) in millimeters as measured along the pitch line. The theoretical pitch line of a PowerGrip GT2 belt lies within the tensile member. 5mm pitch, 9mm wide Long-Length Belting is designated as LL5MR-09. Belting is available in lengths up to 300 ft.
5mm PowerGrip® GT®2 – Belt Sizes Available
Pitch Pitch Pitch
Part No. of Length Part No. of Length Part No. of Length
No. Teeth (In.) No. Teeth (In.) No. Teeth (In.)
5MR-300-09 60 11.81 5MR-575-09 115 22.64 5MR-900-09 180 35.43
5MR-355-09 71 13.98 5MR-580-09 116 22.83 5MR-1000-09 200 39.37
5MR-375-09 75 14.76 5MR-600-09 120 23.62 5MR-1150-09 230 45.28
5MR-400-09 80 15.75 5MR-625-09 125 24.61 5MR-1300-09 260 51.18
5MR-405-09 81 15.95 5MR-650-09 130 25.59 5MR-1450-09 290 57.09
5MR-425-09 85 16.73 5MR-700-09 140 27.56 5MR-1600-09 320 62.99
5MR-450-09 90 17.72 5MR-750-09 150 29.53 5MR-1720-09 344 67.72
5MR-500-09 100 19.69 5MR-800-09 160 31.5 5MR-1755-09 351 69.09
5MR-535-09 107 21.06 5MR-815-09 163 32.09 5MR-2100-09 420 82.67
5MR-565-09 113 22.24 5MR-850-09 170 33.46
No. of Pitch Dia.No. Grooves (In.)
P12-5M-09AL 12 .752
P13-5M-09AL 13 .815P14-5M-09AL 14 .877P15-5M-09AL 15 .940P16-5M-09AL 16 1.003P17-5M-09AL 17 1.065P18-5M-09AL 18 1.128P19-5M-09AL 19 1.191P20-5M-09AL 20 1.253P22-5M-09AL 22 1.379P24-5M-09AL 24 1.504P25-5M-09AL 25 1.566P26-5M-09AL 26 1.629P28-5M-09AL 28 1.754P30-5M-09AL 30 1.880P32-5M-09AL 32 2.005P34-5M-09AL 34 2.130P36-5M-09AL 36 2.256P38-5M-09AL 38 2.381P40-5M-09AL 40 2.506P44-5M-09AL 44 2.757P48-5M-09AL 48 3.008P50-5M-09AL 50 3.133P56-5M-09AL 56 3.509P60-5M-09AL 60 3.760P62-5M-09AL 62 3.885P70-5M-09AL 70 4.386P72-5M-09AL 72 4.511
5mm pitch aluminum sprockets available for 9mm and 15mm wide belts. (For 15mm width, please change end part number from 09AL to 15AL) A complete drive system includes the sprocket hardware, available from Gates as well.
5mm PowerGrip® HTD® – Sprockets Available
Gates sells all products only through our Distributor network. The Gates.com website has this information.
Your best sources that will take credit card orders and expedite delivery are:
B & B Manufacturing, La Porte, IN
bbman.com or 877-787-4022
York Industries Garden City, NY
York-ind.com 800-354-8466
Stock Drive Products- New Hyde Park, NY
Sdp-si.com 516-328-3300
Buying Additional Parts
Download (PDF) your copy from www.gates.com
See URL below, or click through: www.gates.com Power Transmission Catalogs Drive Design Manuals
PowerGrip GT2 – Design Manual
http://www.gates.com/catalogs/index.cfm?requesting=ptcatalog&location_id=524#ddm
The June 2007 GatesPower Transmission catalog is available on www.gates.com
Includes all PowerGrip GT2 components in your kit, as well as all available sizes
http://www.gates.com/catalogs/index.cfm?requesting=ptcatalog&location_id=524#ddm
Gates Industrial Power Transmission Catalog
For additional questions or product-related orders, please email the PowerGrip team at [email protected] or the Gates Product Application Help Line at 303-744-5800
Best of luck in your FIRST competitions! Feel free to contact us before, during, and
after the competition for any questions, opportunities, or inquiries you may have
Contact The PowerGrip Team
SynchronousSynchronousSynchronousSynchronous
•Poly ChainPoly Chain®® GT GT®® CarbonCarbon-- Improved High Performance Belt Improved High Performance Belt Constructed with Polyurethane Body and Constructed with Polyurethane Body and CarbonCarbon Fiber Tensile Cord (approx 15% Fiber Tensile Cord (approx 15% greater capacity than “old” PCGT2). More length stable. More flesible greater capacity than “old” PCGT2). More length stable. More flesible (accomodates back-side idlers well)(accomodates back-side idlers well)
• Pitches Available – 8MPitches Available – 8M• 14M14M