In Synchronous Belts transmission, the pitch center line where the force acts is outside the tip of Belt Sprockets teeth, so transmission is possible by applying the appropriate tension.

For normal power transmission applications, it is recommended that you set installation tension based on the recommended value listed in the catalog.

Also, if positioning accuracy is important for your application, set the value higher, but not exceeding the maximum value listed in the catalog.

If you set installation tension below the recommended value due to the load conditions or equipment conditions, please check that this does not increase vibration or noise, or cause problems with transmission such as skipped teeth.

If installation tension is too high or too low, it may cause premature failure of Synchronous Belts.

It is preferable to adjust by moving one of the axes, but it is also possible to provide an idler for adjustment.

As a general rule, the idler should be installed on the slack side of Synchronous Belts so that it can be fixed after adjustment.

1. ①Using the Tsubaki Belt Tension Meter T-ACE^​​

   You can easily and accurately check the tension by using the Tsubaki Belt Tension Meter T-ACE ^​, an ultrasonic belt tension meter that measures the belt's natural frequency.

2. ②You can check by pressing Synchronous Belts and seeing the amount of deflection that occurs.
   1. Accurately determines the parallelism of all shafts, including idler shafts, and the alignment of pulleys.
   2. Pressing force (F) is applied to the center of Synchronous Belts span.
   3. Apply tension so that Synchronous Belts deflection (δ) is 1.6 mm per 100 mm span.

[Click to enlarge]

• 

  
  F: Pressing force N{kgf} required for deflection (δ) at the center of span t
• Ti: installation tension N{kgf}
• Y: Correction coefficient
• δ: Deflection mm=0.016t
• t: span length mm
• C: Center distance mm
• Dp: Large pulley pitch circle diameter mm
• dp: Small pulley pitch circle diameter mm
• L: Belt length mm

For two shafts (two Belt Sprockets), measure at the center of the span.

In the case of multiple axes (three or more Belt Sprockets /idlers), measure at the point with the longest span. This will allow for more stable measurements.

It is possible to reduce installation tension to a level where tooth skipping does not occur. The occurrence of tooth skipping varies depending on the operating conditions, so please check with the actual machine.

Even if Synchronous Belts Belt Sprockets is properly aligned, the timing belt does not run in the center of Belt Sprockets, but tends to lean to one side.

Although this force is very weak, if Belt Sprockets is not properly aligned, it may run close to the edge of Belt Sprockets and be pressed hard against the guide flange, potentially damaging or cutting it.

Also, the guide flange may fall off.

Adjust Belt Sprockets alignment to within the tolerances in the table below.

■ Pulley adjustment method

There are two types of stretch that can occur in Synchronous Belts.

1. ① Elastic elongation (load elongation)

   This is a reversible stretch that occurs when a load is applied to Synchronous Belts. It returns to its original shape when the load is removed.

2. ② Permanent elongation (operating elongation)

   This stretching does not return to its original state even after the load on Synchronous Belts is removed. It is mainly caused by initial break-in and wear.

In an improperly selected Synchronous Belts, tooth fabric wears and eventually the belt teeth fall off.

Additionally, if the diameter of Belt Sprockets is small or if there are many bends in the multi-axis layout, the core wire may become fatigued due to bending and break.

As shown above, Synchronous Belts reaches the end of its life when it loses its ability to accurately mesh with Belt Sprockets and transmit power.

Inspect Synchronous Belts regularly, and if any abnormalities such as scratches are found on the exterior or tooth fabric is worn, replace it before the belt teeth are missing or Synchronous Belts breaks.

The end of life can manifest as vibrations or noise, but these can be subtle and difficult to detect in advance.

Inspect Synchronous Belts regularly and if you notice any scratches or other abnormalities or wear on tooth fabric, replace it before the belt teeth are missing or broken.

With the Tsubaki Ultra PX^​ belt, wear on the tooth cloth can be easily confirmed by the exposed rubber, making it easy to determine when it needs to be replaced.

Before use

After use

Synchronous Belts are not made of metal and therefore do not have a fatigue limit. As they are used, fatigue and wear occur, eventually leading to breakage.

Furthermore, since the durability period varies greatly depending on the conditions and layout of use, it is very difficult to determine when the lifespan will be reached.

We recommend replacing the filter every 5 years at most, taking into account the aging of the material.

Unlike metal chains or gears, Synchronous Belts teeth are made of rubber covered with nylon fabric, so they are not suitable for transmitting power with just one tooth; multiple teeth are required to support the load. If there are less than six teeth meshing with Belt Sprockets, the load per tooth will be large and may cause tooth chipping.

If the number of meshing teeth is 5 or 4, please add the "meshing correction coefficient" listed in the catalog when making your selection.

For drive pulleys, please consider using a minimum of six meshing teeth with a meshing angle of 120 degrees or greater.

This combination requires the small diameter pulley to rotate at high speed, which accelerates bending fatigue of the core wire inside Synchronous Belts and shortens its lifespan, so please avoid using it.

If Synchronous Belts circumferential speed is high, the following may occur:

1. ①The centrifugal tension generated in Synchronous Belts may reduce the power transmission capacity.
2. ②The lifespan may be shortened.
3. 3) If Belt Sprockets speed exceeds 33 m/s, runout and vibration may occur, so be sure to maintain balance.

When selecting Synchronous Belts, we recommend that you consider the torque based on the servo motor's characteristics.

We can manufacture belts with a certain width, so please contact our customer service or a retailer.

The guideline is 1.5 times the total height of Synchronous Belts, but this varies depending on the model, so please contact our customer service center or a dealer.

Since endless Synchronous Belts are manufactured using molds, we cannot manufacture belt lengths that are not listed in the catalog.

The oil resistance of the "Ultra PX Belt" is based on the results of various tests conducted by our company using general lubricating oils and cutting oils, so we do not guarantee resistance to all types of oil or usage conditions.

Please check the actual equipment or contact us to see if it is suitable for a particular oil type or operating conditions.

Generally, if oil or water gets on Synchronous Belts, it will swell and will not mesh with Belt Sprockets, causing a decrease in transmission capacity and early damage. In particular, timing belts cannot be used in oil or water.

We offer a lineup of "Ultra PX Belt Oil-Resistant Specification" and "PX Belt Water-Resistant Specification" that have enhanced durability in environments with oil or water mist.

Please use in a normal environment of -15℃ to 80℃. There are Synchronous Belts that can be used up to 90℃ under certain conditions.

For details, please contact our customer service.

The "PX tooth profile" is our own unique tooth profile and is not compatible with other companies' tooth profiles, so please use it in combination with a Tsubaki Belt Sprockets.

Important points to note are listed in the "Synchronous Belts Transmission" catalog. Please be sure to read the "Instruction Manual" page before use.

Synchronous Belts do not stretch even when force is applied.

When installing on Belt Sprockets, move the pulley shaft and idler shaft before installing.

Forcing Belt Sprockets over the guide flange may result in an accident, so please avoid doing so.

In two-shaft transmissions that do not use idlers, provide some adjustment space for the distance between the shafts.

■ Adjust the distance between the two shafts

Unit: mm

	Belt length	kinds
		P2M・P3M・P5M UP3M・UP5M	P8M・P14M UP8M・UP14M
△Co	Under 500	3	3
	500～1000	5	5
	1001～2000	10	10
	Over 2000	15	15
△Ci	common	10	15

[Click to enlarge]

Use in a clean atmosphere.

If Synchronous Belts and pulley with a cover. Please consider using the "Ultra PX Belt Oil-Resistant Specification" in an environment with a lot of moisture or oil in the air, and the "PX Belt Water-Resistant Specification" in an environment with a lot of moisture.

Generally, it is as follows:

1. ①The impact noise that occurs when the bottom of Synchronous Belts tooth root hits the top of Belt Sprockets teeth.
2. ② Synchronous Belts string vibration noise
3. 3) Friction noise caused by Synchronous Belts teeth rubbing against Belt Sprockets teeth and meshing.
4. 4) Friction noise caused when the side of Synchronous Belts rubs against the guide flange of Belt Sprockets
5. ⑤ When Synchronous Belts and Belt Sprockets are engaged, the air discharge noise occurs when the air is discharged from Belt Sprockets tooth groove.

1. (1) The natural frequency of Synchronous Belts is changed by changing installation tension, pulley rotation speed, belt length, belt width, number of pulley teeth, etc.
2. ② Change to a high-strength Synchronous Belts and narrow the belt width.
3. ③ Narrow the belt width and change to multiple strand hanging.
4. ④ Adjust the alignment of Belt Sprockets to prevent Synchronous Belts from contacting the guide flange.

Compliant with the RoHS directive.

The maximum is about 98%.

[Exterior features]

The belt is cut parallel to the teeth, and the core wires are also cut short and even.

[Probable cause]

1. ① The core wire was broken due to excessive bending during storage or assembly.
2. ②The pulley diameter was too small, causing the core wire to break.

[countermeasure]

1. 1. Take care when storing or assembling to avoid excessive bending. Do not bend to a diameter less than four times the pitch.
2. ② Check that the diameters of Belt Sprockets and idler are appropriate. If they are too small, change them to the appropriate diameters. Check Belt Sprockets diameter in kW ratings table, and the idler diameter in the table below.

• Inner idler: Belt Sprockets with at least the minimum number of teeth shown in the table below.
• Outer idler: A flat pulley with no crown, with a diameter at least 1.2 times the pitch circle diameter of the pulley in the table below.

■ Minimum number of pulley teeth when selecting an idler

kinds	Rotational speed r/min
	Under 900	Over 900 Under 1200	Over 1200 Under 1800	Over 1800 3600 or less
P2M	16	16	18	20
P3M・UP3M	14	14	16	18
P5M・UP5M	18	20	24	28
P8M・UP8M	24	26	26	28
P14M・UP14M	28	28	28	34

Note: For speeds exceeding 3600 r/min, refer to the standard transmission capacity table.

Inner idler

Outer idler

[Exterior features]

• Tooth fabric has become fuzzy, turned whitish, and the weave has become unclear.
• Tooth fabric is worn and the rubber is exposed.
• The belt teeth become thinner.
• Tooth fabric at tooth root is worn and the core wire is exposed.

[Probable cause]

1. 1. Overload occurs.
2. ② Excessive installation tension.
3. 3) Insufficient installation tension.
4. ④Insufficient Synchronous Belts capacity.
5. ⑤ Improper tooth profile or tooth dimensions of Belt Sprockets.
6. ⑥Use in a dusty atmosphere.

[countermeasure]

1. (1) Check the specifications of the prime mover, the inertia of the driven machine, and the conditions of use, and eliminate the cause of the overload, or increase the size of Synchronous Belts and pulley.
2. ②Adjust installation tension to the appropriate level.
3. 3) Adjust installation tension to the appropriate level.
4. 4) Check the operating conditions and select the optimum size Synchronous Belts and pulley.
5. 5) Replace Belt Sprockets with one that has the correct tooth profile and dimensions.
6. ⑥ Prevent dust from adhering to Synchronous Belts and pulleys by improving the atmosphere or installing a cover.

[Probable cause]

1. 1) Overload (shock load) occurs.
2. ②Insufficient installation tension.
3. 3) Insufficient number of meshing teeth with Belt Sprockets.
4. 4) Insufficient rigidity of the frame.

[countermeasure]

1. 1) Remove the cause of the shock load, or install a shock absorbing mechanism, or increase the size of Synchronous Belts.
2. ②Adjust installation tension to the appropriate level.
3. 3) Increase the number of teeth on Belt Sprockets, or install an idler to increase the number of meshing teeth.
4. ④ Increase the rigidity of the stand.

[Exterior features]

• Cracks have occurred at the base of the belt teeth.
• Belt teeth are missing.

[Probable cause]

The suspected causes are the same as those for "Q30 Synchronous Belts tooth wear" and "Q31 Synchronous Belts tooth skipping." Continuing these conditions leads to shear fracture.

[countermeasure]

Please refer to the countermeasures for "Q30 Synchronous Belts tooth wear" and "Q31 Synchronous Belts tooth skipping" as they are the same.

[Exterior features]

• The corners of the sides are rounded.
• The rubber on the side appears to have been ripped off.
• The core wire is frayed and exposed.

[Probable cause]

1. ①Poor parallelism of the shaft.
2. ② Belt Sprockets misalignment.
3. 3) Insufficient rigidity of the frame.
4. ④ Deformation of Belt Sprockets guide flange.

[countermeasure]

1. ①Adjust the parallelism of the shaft correctly.
2. ② Adjust Belt Sprockets to the correct position.

   Belt size	All varieties
   Belt width mm	30 or less	30～50	50～100	Over 100
   Allowable parallelism	5/1000 or less	4/1000 or less	3/1000 or less	2/1000 or less
   θ minutes	17 or less	13 or less	10 or less	6 or less

   
   [Click to enlarge]

   ■ Pulley adjustment method

   As shown in the figure, a straight edge is placed on the reference pulley, and the other pulleys are brought into contact with the entire surface of the straight edge (ε = 0), allowing the pulleys to be lined up in the correct position.

   In addition, by keeping δ in the figure below the limit, it is possible to simultaneously achieve parallelism of the axis.

   
   [Click to enlarge]

3. 3) Increase the rigidity of the stand.
4. ④Replace with a new one.

[Exterior features]

• There is a scratch perpendicular to the belt teeth.

[Probable cause]

1. 1) Running over the edge of Belt Sprockets.
2. ② Belt Sprockets rides up onto the guide flange.

[countermeasure]

1. ① The shaft parallelism or Belt Sprockets position is incorrect, so adjust it to the correct position.
2. ②If the shaft parallelism or Belt Sprockets position is incorrect, adjust it to the correct position.

   Check installation tension, and if it is insufficient, adjust it to the appropriate installation tension.

[Exterior features]

• It is partially cut off.
• Scratches may be found on the tooth surface other than the cut area.

[Probable cause]

1. 1) Belt Sprockets rides up onto the guide flange.
2. ②Foreign objects are caught.

[countermeasure]

1. 1) If the shaft parallelism or Belt Sprockets position is incorrect, adjust it to the correct position.

   Check installation tension, and if it is insufficient, adjust it to the appropriate installation tension.

3. ②Improve the atmosphere or install a cover to prevent foreign matter from adhering to Synchronous Belts and pulley.

[Exterior features]

• The rubber is bulging.

[Probable cause]

• The rubber absorbed the oil and moisture that had adhered to Synchronous Belts.

[countermeasure]

• To prevent oil and moisture from adhering to Synchronous Belts, improve the atmosphere or install a cover.
• It may be possible to replace it with the "Ultra PX Belt Oil Resistant Specification," so please consider this.

[Probable cause]

The movement of the axes brings them closer together.

[countermeasure]

Secure the shaft firmly.

[Exterior features]

• There is softened rubber on the back of Synchronous Belts.
• Synchronous Belts rubber is sticky or soft.

[Probable cause]

1. ①Oil adhered to Synchronous Belts and was absorbed by the rubber.
2. ②Use in high temperature atmosphere.
3. 3) Poor rotation of outer idler

[countermeasure]

1. ① Improve the atmosphere or install a cover to prevent oil from adhering to Synchronous Belts.

   It may be possible to replace it with the "Ultra PX Belt Oil Resistant Specification," so please consider this.

2. ② Lower the ambient temperature to 80°C or below.
3. 3) Adjust the idler so that it rotates. For example, reduce the idler inertia or increase the bearing size.

[Exterior features]

• There is a depression on the back surface parallel to the end face.
• The mark on the back has disappeared or is about to disappear.

[Probable cause]

1. 1) Poor alignment of outer idler shaft.
2. ②Outside idler is not rotating properly.

[countermeasure]

1. ① The parallelism of the shaft is incorrect, so adjust it to the correct position.
2. ② Adjust the idler so that it rotates. For example, reduce the idler inertia or increase the bearing size.

[Exterior features]

• There is a crack on the back of Synchronous Belts parallel to the teeth.

[Probable cause]

1. ①The diameter of Belt Sprockets or idler being used is too small.
2. ② The ambient temperature is too high or too low.

[countermeasure]

1. ① Check that the diameter of Belt Sprockets and idler is appropriate. If it is too small, change it to one with the appropriate diameter.

   (Check Belt Sprockets diameter in kW ratings table, and the idler diameter in the table below.)

   • Inner idler: Belt Sprockets with at least the minimum number of teeth shown in the table below.
   • Outer idler: A flat pulley with no crown, with a diameter at least 1.2 times the pitch circle diameter of the pulley in the table below.

   ■ Minimum number of pulley teeth when selecting an idler

   kinds	Rotational speed r/min
   	Under 900	Over 900 Under 1200	Over 1200 Under 1800	Over 1800 3600 or less
   P2M	16	16	18	20
   P3M・UP3M	14	14	16	18
   P5M・UP5M	18	20	24	28
   P8M・UP8M	24	26	26	28
   P14M・UP14M	28	28	28	34

   Note: For speeds exceeding 3600 r/min, refer to the standard transmission capacity table.

   

   Inner idler

   

   Outer idler

2. ②Improve the ambient temperature to -15℃ to 80℃, at which point Synchronous Belts can be used.

[Exterior features]

• The part that engages with Synchronous Belts has worn out, creating a step where it does not engage.
• The tooth surface is rough.

[Probable cause]

1. 1) Belt Sprockets material is inappropriate.
2. ② It was used in a dusty environment and was operated with abrasive dust adhering to Synchronous Belts and pulley.
3. 3) Synchronous Belts installation tension was too high.

[countermeasure]

1. 1) Change to a material with higher hardness, harden the tooth surface, or perform a surface treatment to improve wear resistance.
2. ②Improve the operating environment or install a cover to prevent dust from adhering.
3. 3) Adjust installation tension to the appropriate level.

Synchronous Belts vibration frequency for the BDTM101 is 30 to 600 Hz, and for the BDTM201 it is 10 to 5000 Hz.
If the measurement span is too short or too long, the vibration frequency may be outside the measurable range and may not be measurable.

We are offering demo units for loan. Please contact our customer service for details.

This service is available for a fee. Please inquire with a retailer that handles our products.

Please set the calibration interval according to your own standards and judgment.

High strength aluminum with white alumite finish.

We will consider whether it is possible to manufacture the product, so please contact a dealer that handles our products with your drawings attached.