Precautions when installing Lock Belt Sprockets

• Always use a torque wrench when tightening the clamping bolts. Observe the tightening instructions and tightening torque MA. Using a wrench other than a torque wrench or tightening by hand will result in inaccuracy and may lead to accidents such as slippage or deformation.
• Tightening a bolt with a torque greater than the specified torque may cause the bolt to break. Tightening a bolt with a torque less than the specified torque may cause the bolt to loosen, so be sure to tighten it to the specified torque MA.
• Do not use any tightening bolts other than those provided with this product. Doing so may result in damage to the bolts or other accidents. If you need new bolts due to loss or replacement, please contact us.

1. Use the simple selection table in the Tsubaki Synchronous Belts transmission catalog to provisionally select the belt size based on the design power and small pulley rotation speed.
2. Please provisionally select the belt width and number of teeth on the pinion pulley from the standard transmission capacity table in the catalog. When doing so, please note the following:
• Select a pinion tooth number other than the colored part of the standard transmission capacity.
• Select a small pulley so that its pitch diameter is greater than the belt width.
• Make sure that the usable range of the pinion shaft hole satisfies the diameter of the shaft being used.
3. Determine the number of teeth on the large pulley based on the number of teeth on the small pulley and the speed ratio. Also, check the shaft bore diameter to be used.

1. Use the simple selection table in the Tsubaki Synchronous Belts transmission catalog to provisionally select the belt size based on the design torque and small pulley rotation speed.
2. Please provisionally select the belt width and number of teeth on the pinion pulley from the standard transmission torque table in the catalog. When doing so, please note the following:
• Select a pinion tooth number other than the colored portion of the standard transmission torque.
• Select a small pulley so that its pitch diameter is greater than the belt width.
• Make sure that the usable range of the pinion shaft hole satisfies the diameter of the shaft being used.
3. Determine the number of teeth on the large pulley based on the number of teeth on the small pulley and the speed ratio. Also, check the shaft bore diameter to be used.

Unlike metal chains and gears, Synchronous Belts teeth are made of rubber covered with nylon fabric, so they are not suitable for transmission with just one tooth; multiple teeth are required to bear the load.

If the number of meshing teeth with Belt Sprockets is less than 6, 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 selecting a pulley.

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

The combinations shown in the colored sections of kW ratings table in Synchronous Belts transmission catalogue should be avoided as they will cause the small pulley to rotate at high speeds, accelerating bending fatigue of the core wire inside Synchronous Belts and shortening its lifespan.

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

• 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.

The following pulley materials are suitable:

Various surface treatments are possible depending on the application, so please consider them.

Synchronous Belts normally have backlash when meshing, but for Synchronous Belts drives that require extremely accurate rotation, such as robots, electronic component assembly machines, NC devices, printers, and plotters, we manufacture pulleys with special backlash-free tooth profiles that reduce backlash and suppress rotation Angular Misalignment, so please contact us for details.

Pulleys with dimensions, number of teeth, and materials other than those listed in the catalogue can also be manufactured, so please contact our customer service or a dealer.

Use in a normal environment with a temperature range of -15°C to 80°C (aluminum: 0°C to 50°C).

The pulleys for Tsubaki PX Belt have our own unique tooth shape and cannot be used with other companies' belts.
Please use in combination with Tsubaki Synchronous Belts.

Important points to note are listed in the "Belt Sprockets" 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.

For pulleys, stainless steel specifications that are effective in corrosion resistance and chemical resistance, or surface treatment specifications that are effective in rust prevention may be available, so please consider these.

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.

All of our products are sold through distributors, so please inquire about prices and delivery with your local dealer.

There is a risk of premature breakage of Synchronous Belts.

[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

This can cause the rubber on the back of Synchronous Belts to crack.

[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.

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.)

   ■ Idlers are used in the following cases:

   • When the bearing is fixed and installation tension is adjusted
   • When the speed ratio is large and the number of meshing teeth of the small pulley is increased
   • When belt guides cannot be used on drive and driven pulleys

   ■ Precautions when using idlers

   • The idler should be fixed and, in principle, used on the slack side.
   • Please note that if the idler is not properly aligned, the idler will cause the belt to slip off the pulley.
   • Determine the idler diameter as follows:
   • 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.

[Exterior features]

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

[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. ⑥ Use in a dusty atmosphere.

[countermeasure]

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

There is a risk of Synchronous Belts teeth skipping.

[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 stand.

[countermeasure]

1. 1) Remove the cause of the shock load, or install a shock absorbing mechanism, or increase the size of Synchronous Belts.
2. ② Adjust 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.

Synchronous Belts side wear and tear

[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.

   ■ Pulley alignment

   Even if the pulley alignment is correct, Synchronous Belts does not rotate in the center of the pulley, but tends to lean to one side.

   Although this force is very weak, if the pulley is not properly aligned, the belt will be pressed hard against the pulley flange, causing damage and breakage.

   Therefore, adjust the pulley alignment within the tolerances in the table below.

   ■ Pulley alignment tolerance

   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.