People often call to ask where they can get drawings of CAD files for our belts and sheaves. There are two places to look. The easiest is our online catalog:
www.gates.com/partview
By searching your part number in the top left, you can go directly to the product page. Each page has a general product overview with basic dimensions and information. A 2D spec sheet is usually available in the bottom of the "Attachments" section, and a 3D CAD model may be available to download near the top of the page.
If information is not available on PartView, you can find detailed sprocket specification tables in our drive design manuals. The manuals are broken down into belt lines such as Poly Chain GT Carbon, PowerGrip GT2 and Heavy Duty V-Belt. Small pitch (2, 3, 5mm) synchronous belts including PowerGrip GT2, HTD and Timing will be located in our Light Power and Precision Manual. All of these manuals are available to download along with our catalog here:
http://gates.com/catalogs/index.cfm?requesting=ptcatalog&location_id=2999
These manuals also contain horsepower ratings and many other great design and engineering resources.
GATES BELTS, HOSES, AND APPLICATIONS
Tuesday, December 28, 2010
Tuesday, December 21, 2010
Safety First
Gates publishes a detailed Preventive Maintenance manual, with strong content regarding safety practices. Most of these are common sense - lock out the drive before touching the mechanical system, for example.
When working with any electrical power source, take extra care to make sure to avoid any hazardous situations. Many years ago, during a power survey, I had a near miss when hooking up a data logger in the power supply box. While I had many, many, experiences setting up the test equipment, this particular time I was shocked (literally) when clamping on an amperage probe. I was very lucky - just a few hours of a numb arm and no lasting effects.
What is the point? Never assume that the system is safe. Ask, ask again, and double check to make sure every appropriate safety precaution has been properly taken before working on a belt drive system. Accidents happen because people get in a hurry, or overlook the obvious, or make an improper assumption. Remember - you're talking about your health - act accordingly and be mindful of the proper safety measures when doing any installation or maintenance work.
When working with any electrical power source, take extra care to make sure to avoid any hazardous situations. Many years ago, during a power survey, I had a near miss when hooking up a data logger in the power supply box. While I had many, many, experiences setting up the test equipment, this particular time I was shocked (literally) when clamping on an amperage probe. I was very lucky - just a few hours of a numb arm and no lasting effects.
What is the point? Never assume that the system is safe. Ask, ask again, and double check to make sure every appropriate safety precaution has been properly taken before working on a belt drive system. Accidents happen because people get in a hurry, or overlook the obvious, or make an improper assumption. Remember - you're talking about your health - act accordingly and be mindful of the proper safety measures when doing any installation or maintenance work.
Thursday, December 16, 2010
Finding NEMA
If you are using an electric motor to run your belt drives and are having problems with the life of the bearings and/or shafts, your motor pulley may be smaller than recommended. As the pulley size on the motor decreases, the magnitude of the belt pull increases, thus exerting a higher load on the bearings and shafts of the motor. NEMA (National Electrical Manufacturers Association) issues a list of minimum recommended sizes for various NEMA frame electric motors. Staying above these values should extend the life of the bearings and shafts on the motor and should prevent any premature failures from occurring. Below is the NEMA table taken out of the Gates Polychain Carbon Drive Design Manual:
Tuesday, December 7, 2010
What Belt Length Do I Need?
One of the most common questions we get is: “What belt length do I need?” Well, there are a couple of ways to figure this out. First, lets do it the hard way. You can use the equation:
Lp = 2C + 1.57(D + d) + ((D – d)^2 / 4C)
Where:
Lp = belt pitch length, inches
D = diameter of large sprocket, inches
D = diameter of small sprocket, inches
C = center distance, inches
Now if doing the math isn’t for you, there are a couple of easier ways to get this figured out. I would recommend our free software. We offer both Design Flex (Web and Pro versions), and Design IQ. You can download either of these at www.gates.com/drivedesign Design Flex is a two point drive design program that is tailored to help you easily design drives, and find proper tension. Design IQ is a little more complex; it is designed to help with drives no matter how many sprockets or sheaves.
With Design Flex, you will need to enter in a load in order to get it to calculate a belt length. While this load doesn’t need to be accurate for calculating belt length, you do need proper loading for trying to design or find the correct tension for a given drive.
With Design IQ, you don’t need to enter a load to get a belt length, but you need to understand where you are placing the sprockets/sheaves. Starting with the driver at the coordinates (0,0), place the driven at the measured center distance in the X coordinate and 0 in the Y coordinate, you can easily find the two belt lengths that are closest (one shorter, and one longer) by selecting the belt length button. When you select one of the belt lengths, the program will then show you what your actual center distance will be in the driven sprockets/sheave’s X coordinate box.
As always, if you have any questions, or would like us to walk you through an example of how to do this, you can call us at 303-744-5800.
Lp = 2C + 1.57(D + d) + ((D – d)^2 / 4C)
Where:
Lp = belt pitch length, inches
D = diameter of large sprocket, inches
D = diameter of small sprocket, inches
C = center distance, inches
Now if doing the math isn’t for you, there are a couple of easier ways to get this figured out. I would recommend our free software. We offer both Design Flex (Web and Pro versions), and Design IQ. You can download either of these at www.gates.com/drivedesign Design Flex is a two point drive design program that is tailored to help you easily design drives, and find proper tension. Design IQ is a little more complex; it is designed to help with drives no matter how many sprockets or sheaves.
With Design Flex, you will need to enter in a load in order to get it to calculate a belt length. While this load doesn’t need to be accurate for calculating belt length, you do need proper loading for trying to design or find the correct tension for a given drive.
With Design IQ, you don’t need to enter a load to get a belt length, but you need to understand where you are placing the sprockets/sheaves. Starting with the driver at the coordinates (0,0), place the driven at the measured center distance in the X coordinate and 0 in the Y coordinate, you can easily find the two belt lengths that are closest (one shorter, and one longer) by selecting the belt length button. When you select one of the belt lengths, the program will then show you what your actual center distance will be in the driven sprockets/sheave’s X coordinate box.
As always, if you have any questions, or would like us to walk you through an example of how to do this, you can call us at 303-744-5800.
Monday, November 29, 2010
Design Flex Force/Deflection Tensioning
We often get questions from customers about the force/deflection tensioning recommendations on a Design Flex printout. The report lists the "Rib/Strand Deflection Distance" and the "Rib/Strand Deflection Force" for both a new and used belt. If you have never used this method of measuring tension, our Belt Drive Preventive Maintenance and Safety Manual has thorough instructions.
Some people think that you can measure the tension by only measuring deflection. However, in order to properly tension a belt, you must measure both the force and deflection distance. Measuring one inch of deflection with 5lbs of force is a very different tension than one inch of deflection that requires 100lbs of force.
Some confusion arises from the "Rib/Strand" portion of the title. For a synchronous drive, there is almost always only one belt, so you can use the listed force/deflection values. V-belts however, often have more than one belt on the same drive. In order to properly tension the drive you must multiply the deflection force by the number of strands that you will be deflecting. Even though your PowerBand belt looks like a single belt, you must multiply the force by the number of ribs. The deflection distance is not multiplied by the number of ribs and is calculated as 1/64 of an inch per inch of span length.
People also wonder what is considered to be a used belt. Any belt that has not been run more than about 24 hours is considered a new belt. If you are reassembling a drive with the same belt that was used previously, it is recommended that you measure the tension before dis-assembly and reinstall it at the same tension. If you did not measure the tension, you can reinstall with the used belt values.
Some people think that you can measure the tension by only measuring deflection. However, in order to properly tension a belt, you must measure both the force and deflection distance. Measuring one inch of deflection with 5lbs of force is a very different tension than one inch of deflection that requires 100lbs of force.
Some confusion arises from the "Rib/Strand" portion of the title. For a synchronous drive, there is almost always only one belt, so you can use the listed force/deflection values. V-belts however, often have more than one belt on the same drive. In order to properly tension the drive you must multiply the deflection force by the number of strands that you will be deflecting. Even though your PowerBand belt looks like a single belt, you must multiply the force by the number of ribs. The deflection distance is not multiplied by the number of ribs and is calculated as 1/64 of an inch per inch of span length.
People also wonder what is considered to be a used belt. Any belt that has not been run more than about 24 hours is considered a new belt. If you are reassembling a drive with the same belt that was used previously, it is recommended that you measure the tension before dis-assembly and reinstall it at the same tension. If you did not measure the tension, you can reinstall with the used belt values.
Tuesday, November 16, 2010
Minimizing Noise In Synchronous Belt Drive Systems
Drive noise evaluation in any belt drive system should be approached with care. There are many potential sources of noise in systems including vibration from related components, bearings, and resonance and amplification through framework and panels. Belt drives sometimes receive blame from noise generation that they don't actually produce.
Noise from synchronous belt drive systems generally results from the process of belt tooth meshing and physical contact with sprockets. The sound pressure level generally increases as operating speed and belt width increases, and as sprocket diameter decreases. Drives designed with moderate sprocket sizes and without excessive capacity (over-design) are generally the quietest.
Proper belt installation tension is very important in minimizing drive noise. Belts should be tensioned at a level that allows them to run with as little meshing interference as possible.
Drive alignment also has a significant effect on drive noise. Special attention should be given to minimizing angular misalignment (shaft parallelism). This assures that belt teeth are loaded uniformly and minimizes side tracking forces against the flanges. Parallel misalignment (sprocket offset) is not as critical of a concern so long as belts are not trapped or pinched between opposite flanges.
Noise from synchronous belt drive systems generally results from the process of belt tooth meshing and physical contact with sprockets. The sound pressure level generally increases as operating speed and belt width increases, and as sprocket diameter decreases. Drives designed with moderate sprocket sizes and without excessive capacity (over-design) are generally the quietest.
Proper belt installation tension is very important in minimizing drive noise. Belts should be tensioned at a level that allows them to run with as little meshing interference as possible.
Drive alignment also has a significant effect on drive noise. Special attention should be given to minimizing angular misalignment (shaft parallelism). This assures that belt teeth are loaded uniformly and minimizes side tracking forces against the flanges. Parallel misalignment (sprocket offset) is not as critical of a concern so long as belts are not trapped or pinched between opposite flanges.
Gates Supports FIRST Robotics 2011 Preseason
Gates is offering free 2011 preseason belt drive components to all interested FIRST Robotics teams. To help teams determine what parts may be needed, Gates has free drive design manuals and design software available at www.gates.com/drivedesign/.
To order parts, first fill out the form at http://www.usfirst.org/roboticsprograms/frc/content.aspx?id=18398 then email the completed form to ptpasupport@gates.com. Please include the team name, number, and the word FIRST in the email subject.
Parts will be ground shipped to the address provided on the form free of charge. The deadline for submitting orders is December 15, 2010.
If you have any questions, please contact Gates Product Application Engineering at 303-744-5800 (Option 2) or email ptpasupport@gates.com. Gates reserves the right to limit the style and quantity of parts provided to each team.
To order parts, first fill out the form at http://www.usfirst.org/roboticsprograms/frc/content.aspx?id=18398 then email the completed form to ptpasupport@gates.com. Please include the team name, number, and the word FIRST in the email subject.
Parts will be ground shipped to the address provided on the form free of charge. The deadline for submitting orders is December 15, 2010.
If you have any questions, please contact Gates Product Application Engineering at 303-744-5800 (Option 2) or email ptpasupport@gates.com. Gates reserves the right to limit the style and quantity of parts provided to each team.
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