Q&A Synchronous Belts / Belt Sprockets
The following is a list of answers for frequently asked questions from our customers. Select questions to view the answers.
Synchronous belt
Words
Tension meter
Q42 | How much is measurable range? |
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Q43 | I want to use it before purchasing. Do you lend it? |
Q44 | Can you calibrate it? |
Q45 | What is the proper calibration period? |
Belt clamp
Q46 | What is the material? |
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Q47 | Can special order products other than those listed in the catalog be manufactured? |
Q1 | Why is tension applied when a synchronous belt is installed? | ||||||||||||||||||||||||||||||||||
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A1 |
With synchronous belt power transmission, pitch center line on which the force acts is outside the tooth tip of belt sprocket, so transmission is possible by applying appropriate tension. It is desirable to set an installation tension for ordinary transmission applications using the recommended value described in the catalog as a guide. For applications where positioning accuracy is important, set it higher within the range that does not exceed the maximum value listed in the catalog. When setting an installation tension below the recommended value due to load condition or convenience of device, set it while checking whether vibration and noise increase and whether there is a problem with transmission such as tooth jumping. Excessively high or low installation tension may result in premature breakage of synchronous belt. Back to questions |
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Q2 | How to apply an installation tension? | ||||||||||||||||||||||||||||||||||
A2 |
While it is preferable to move one of shafts for adjustment, there is also a method of using an idler for adjustment. As a general rule, install the idler on the slack side of the synchronous belt so that it can be fixed after adjustment. Back to questions |
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Q3 | How to check the installation tension? | ||||||||||||||||||||||||||||||||||
A3 |
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Q4 | Where to measure the installation tension? | ||||||||||||||||||||||||||||||||||
A4 |
For 2-shafts (2 belt sprockets), measure at the center of the span. For multiple shafts (three or more belt sprockets and idlers), measure at the point where the span is longest. More stable measurement is possible. Back to questions |
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Q5 | How much is a minimum installation tension? | ||||||||||||||||||||||||||||||||||
A5 |
Installation tension can be lowered to the extent that the tooth jumping does not occur. Occurrence of tooth jumping varies depending on the operating conditions, so please check with the actual machine. Back to questions |
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Q6 | Is it necessary to adjust the alignment of belt sprocket? | ||||||||||||||||||||||||||||||||||
A6 |
Synchronous belt does not run in the center of belt sprocket even if the belt sprocket is aligned correctly, and has property of shifting to either side. Although its force is very weak, poor alignment of belt sprocket may cause it to travel closer to the edge of belt sprocket and be strongly pressed against the guide flange, resulting in damage and cut. Also, the guide flange may fall off. Adjust the alignment of belt sprocket within the allowable range listed below.
■How to adjust the belt sprocket As shown in the diagram, apply the straight edge to the end face of the standard belt sprocket. Make the other belt sprocket contact with straight edge on all faces (to make ε=0), so that the belt sprockets can be aligned in the correct position. Parallelism of shafts can be obtained simultaneously by setting δ in the diagram below the limit. |
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Q7 | What is an elongation of synchronous belt? | ||||||||||||||||||||||||||||||||||
A7 |
There are two types of elongation that occur in synchronous belts.
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Q8 | Under what conditions should synchronous belt be judged to have reached end of life? | ||||||||||||||||||||||||||||||||||
A8 |
With a properly selected synchronous belt, wear of tooth fabric progresses, and then belt teeth are missing. In addition, if diameter of belt sprocket is small or if there is a lot of bending in a multiple-shafts layout, bending fatigue of cord may lead to cutting. As mentioned above, life is when synchronous belt loses its ability to accurately engage and transmit with belt sprocket. Inspect synchronous belt regularly, and if any abnormal symptoms such as scratches or tooth fabric wear are found on appearance, replace it before belt teeth missing or synchronous belt cutting. Back to questions |
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Q9 | Can life be detected prior to synchronous belt breakage? | ||||||||||||||||||||||||||||||||||
A9 |
Life end may appear as vibration or noise, but some are subtle and difficult to know in advance. Inspect synchronous belt regularly, and if any abnormal symptoms such as scratches or tooth fabric wear are found on appearance, replace it before belt teeth missing or synchronous belt cutting. Tsubaki Ultra PX Belt makes it easy to check wear of tooth fabric by exposing base rubber, so it is easy to decide whether to replace it. Before use After use |
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Q10 | How long does synchronous belt reach end of life? | ||||||||||||||||||||||||||||||||||
A10 |
Because synchronous belt is not metallic, there is no fatigue limit, and fatigue and wear will occur during use, resulting in damage. In addition, it is very difficult to specify time to reach life end because durability time varies greatly depending on conditions and layout used. We recommend replacement within max. 5 years, considering aging of material. Back to questions |
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Q11 | Why more than 6 meshing teeth are required? | ||||||||||||||||||||||||||||||||||
A11 |
Unlike metallic chains and gears, synchronous belt's teeth are rubber materials covered with nylon fabric, so they are not suitable for transmission with only one tooth, and must be loaded with multiple teeth. If number of teeth engaged with belt sprocket is less than 6, load per tooth will increase, resulting in tooth chipping. If number of teeth engaged is 5 teeth or 4 teeth, add "meshing correction factor" described in the catalog to select. For drive belt sprockets, make sure that number of teeth engaged should be 6 or more and engagement angle should be 120 degrees or more. Back to questions |
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Q12 | What is the meaning of colored part of transmission capacity table in the catalog? | ||||||||||||||||||||||||||||||||||
A12 |
Avoid using combinations in this part because small diameter belt sprocket rotates at high speed, which promote bending fatigue of synchronous belt cord inside and shortens its life. Back to questions |
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Q13 | What is precaution point when using servo motor? | ||||||||||||||||||||||||||||||||||
A13 |
When the circumferential speed of synchronous belt is fast, the following phenomena may occur.
When selecting a synchronous belt, it is recommended to examine the torque in consideration of the characteristics of servo motor. Back to questions |
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Q14 | Can products be manufactured other than the standardized width listed in the catalogue? | ||||||||||||||||||||||||||||||||||
A14 |
Please contact us as it can be manufactured depending on the belt width. Back to questions |
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Q15 | What is the minimum width that can be manufactured? | ||||||||||||||||||||||||||||||||||
A15 |
Guideline is 1.5 times the total height of syunchronous belt, but it varies depending on product. Please contact us. Back to questions |
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Q16 | Can the belt length that is not listed in the catalogue be manufactured? | ||||||||||||||||||||||||||||||||||
A16 |
Loop type endless synchronous belts are manufactured using a mold, so belt lengths not listed in the catalog cannot be manufactured. Back to questions |
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Q17 | Is "Ultra PX Belt Oil-Proof Type" effective for all types of oils? | ||||||||||||||||||||||||||||||||||
A17 |
Oil resistance of "Ultra PX Belt Oil-Proof Type" is based on the in-house test results using general lubricant and cutting fluid. Therefore, resistance to all oil types and usage conditions is not always guaranteed. Please check by the actual machine or contact us for the applicability of individual oil types and usage conditions. Back to questions |
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Q18 | Can it be used in an atmosphere around oil or water? | ||||||||||||||||||||||||||||||||||
A18 |
Generally, if oil or water adheres to synchronous belt, it will swell and will not engage with belt sprocket, causing a decrease in transmission capacity and premature breakage. Especially, it cannot be used in oil or water. Tsubaki offers "Ultra PX Belt Oil-Proof Type" and "PX Belt Water-Proof Type" that have improved durability in environments where oil and water are misty. Back to questions |
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Q19 | What atmosphere temperature can synchronous belt use? | ||||||||||||||||||||||||||||||||||
A19 |
Use in a normal environment of -15℃ ~ 80℃. Some syncronous belts can be used up to 90℃ under certain conditions. Please contact us for details. Back to questions |
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Q20 | Is it compatible with other companies' products? | ||||||||||||||||||||||||||||||||||
A20 |
PX tooth profile is Tsubaki original tooth profile and is not compatible with other companies. Please use it together with Tsubaki belt sprocket. Back to questions |
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Q21 | What should be careful before using? | ||||||||||||||||||||||||||||||||||
A21 |
Precautions are summarized in the catalog "Synchronous Belts & Belt Sprockets". Be sure to read the "Instruction Manual" pages before use. Back to questions |
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Q22 | What are the precautions when installing a synchronous belt to belt sprockets? | ||||||||||||||||||||||||||||||||||
A22 |
Synchronous belt hardly stretches even when force is applied. Move belt sprocket shaft / idler shaft before installing it on belt sprocket. Do not attempt to over the guide flange of belt sprocket forcibly, as this may cause an accident. For 2-shafts transmission without an idler, prepare an adjusting margin of inter-axial distance. ■Adjusting margin of inter-axial distance
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Q23 | What should be careful about atmosphere when using synchronous belt? | ||||||||||||||||||||||||||||||||||
A23 |
Use the synchronous belts in a clean environment. Protect synchronous belt and belt sprocket by covering it when used in dusty atmosphere where it may be exposed to excessive water, oil or solvents. Please consider "Ultra PX Belt Oil-Proof Type" in an atmosphere with a lot of moisture and oil in the air, and "PX Belt Water-Proof Type" in an atmosphere with a lot of moisture. Back to questions |
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Q24 | What should be careful about when storing synchronous belt? | ||||||||||||||||||||||||||||||||||
A24 |
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Q25 | What kind of noise is there? | ||||||||||||||||||||||||||||||||||
A25 |
Generally, it is as follows.
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Q26 | What are measures against noise? | ||||||||||||||||||||||||||||||||||
A26 |
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Q27 | Does it comply with RoHS Directive? | ||||||||||||||||||||||||||||||||||
A27 |
Compliant with RoHS Directive. Back to questions |
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Q28 | How much is the transmission efficiency of synchronous belt? | ||||||||||||||||||||||||||||||||||
A28 |
Maximum is approximately 98%. Back to questions |
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Q29 | Premature breakage of synchronous belt | ||||||||||||||||||||||||||||||||||
A29 |
[Appearance features ] Breakage is parallel to the belt teeth. The cords are also short and cut. [Possible causes ]
[Action ]
■Minimum number of teeth of belt sprocket for selection of an idler
Note) For revolutions above 3600 r/min, refer to the Standard Transmission Capacity Table. Inside idler Outside idler |
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Q30 | Wear of syncronous belt teeth | ||||||||||||||||||||||||||||||||||
A30 |
[Appearance features ]
[Possible causes ]
[Action ]
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Q31 | Synchronous belt tooth jumping | ||||||||||||||||||||||||||||||||||
A31 |
[Possible causes ]
[Action ]
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Q32 | Shear breakage of synchronous belt teeth | ||||||||||||||||||||||||||||||||||
A32 |
[Appearance features ]
[Possible causes ] Same as the estimated cause of "Q30 Wear of synchronous belt teeth" and "Q31 Synchronous belt tooth jumping". As a consequence of these situations, it leads to shear failure. [Action ] Refer to the same measures as for "Q30 Wear of synchronous belt teeth" and "Q31 Synchronous belt tooth jumping". Back to questions |
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Q33 | Tear and wear of synchronous belt side face | ||||||||||||||||||||||||||||||||||
A33 |
[Appearance features ]
[Possible causes ]
[Action ]
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Q34 | Longitudinal scratches on synchronous belt tooth surface | ||||||||||||||||||||||||||||||||||
A34 |
[Appearance features ]
[Possible causes ]
[Action ]
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Q35 | Partial cut of synchronous belt | ||||||||||||||||||||||||||||||||||
A35 |
[Appearance features ]
[Possible causes ]
[Action ]
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Q36 | Swelling of synchronous belt | ||||||||||||||||||||||||||||||||||
A36 |
[Appearance features ]
[Possible causes ]
[Action ]
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Q37 | Apparent elongation of synchronous belt | ||||||||||||||||||||||||||||||||||
A37 |
[Possible causes ] Proximity of shafts each other due to shafts movement. [Action ] Securely fix the shaft. Back to questions |
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Q38 | Sticky or softened rubber on back of synchronous belt | ||||||||||||||||||||||||||||||||||
A38 |
[Appearance features ]
[Possible causes ]
[Action ]
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Q39 | Wear of rubber on back of synchronous belt | ||||||||||||||||||||||||||||||||||
A39 |
[Appearance features ]
[Possible causes ]
[Action ]
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Q40 | Crack on rubber on back of synchronous belt | ||||||||||||||||||||||||||||||||||
A40 |
[Appearance features ]
[Possible causes ]
[Action ]
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Q41 | Wear of belt sprocket teeth | ||||||||||||||||||||||||||||||||||
A41 |
[Appearance features ]
[Possible causes ]
[Action ]
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Q42 | How much is measurable range? | ||||||||||||||||||||||||||||||||||
A42 |
30 to 600Hz for BDTM101 and 10 to 5000Hz for BDTM201 as a frequency of synchronous belt.
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Q43 | I want to use it before purchasing. Do you lend it? | ||||||||||||||||||||||||||||||||||
A43 |
We are lending out demo machines. Please contact us. Back to questions |
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Q44 | Can you calibrate it? | ||||||||||||||||||||||||||||||||||
A44 |
We accept it for a fee. Please contact us. Back to questions |
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Q45 | What is the proper calibration period? | ||||||||||||||||||||||||||||||||||
A45 |
Set the calibration cycle based on customer rules and judgment. Back to questions |
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Q46 | What is the material? | ||||||||||||||||||||||||||||||||||
A46 |
High-strength aluminum is treated with white anodized aluminum. Back to questions |
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Q47 | Can special order products other than those listed in the catalog be manufactured? | ||||||||||||||||||||||||||||||||||
A47 |
We will examine whether it can be manufactured, so please contact us with a drawing. Back to questions |