Power Transmission Components FAQ

Frequently asked questions about Tsubaki power transmission components.

Torque Limiter

Do Tsubaki friction facings contain any asbestos?

Tsubaki no longer use asbestos in its friction facings. As of September 1990, non-asbestos friction facings are standard. Our materials are a mixture of inorganic & organic fibers: 27%, resin: 15%, additive agent: 31%, reinforcer and filler: 27%.

I want to use the Torque Limiter coupling at a higher rotational speed than the maximum prescribed in the catalog.

If a sprocket with induction-hardened teeth is chosen, TL200-TL700 sizes can be used at a maximum 1800r/min. Any size above this can run at approximately 800r/min.

Can I use a Torque Limiter in environments where water or oil is present?

Standard Torque Limiters cannot work in these environments. If the friction facing is splashed with oil or water, the friction coefficient will change and alter the slip torque. These conditions can also cause the facing of these products to rust. If it is necessary to operate in such environments, please contact Tsubaki to discuss possible measures.

What is the largest size Torque Limiter/ coupling Tsubaki can manufacture?

Up to 15,000N·m. If a slip torque of more than 15,000N·m is necessary, please consult Tsubaki.

What is the difference between TL250-1 and TL250-2?

The last number indicates the number of disk springs. TL250-2 has 2 pieces of the same disk spring TL250-1 uses, positioned together, facing the same direction. Therefore, the torque setting of TL250-2 is doubled when the nut is tightened at the same amount as TL250-1. All other parts are the same.

What is the bushing's function?

When the Torque Limiter slips, the bushing receives the radial load on the hub.

Can Tsubaki supply finished bores?

Our finished bore and keyway products are made with a bore tolerance of H7. Special finish bores may be available on request. Please contact Tsubaki for more information.

How do you set the torque (models TL200 to TL700)?

Torque is set by adjusting the locking nut or bolt (depending on model). It is a simple process requiring no special tools and full instructions are included with each Torque Limiter supplied.

Can Tsubaki set the torque at the factory?

Torque settings for Torque Limiters & Torque Limiter couplings can be factory set before delivery. For the finished bores and with center members, this must be done at the factory. Set torque value (kgf·m) by the last number in the model reference. For example, TL250-1-04022-18J-1.0 (torque setting of 1.0kgf·m).

When slippage occurs due to overload, can it be detected electronically?

When the torque limiter slips the decrease in rotating speed can be detected by using a proximity switch and digital tachometer. Please refer to the catalog for some examples.

Can I order TL250 friction facings and disk spring(s) separately?

Yes, you can. The friction facing is replacement is TL250A and the disk spring is TL250S.

Do the Torque Limiter & Torque Limiter couplings conform to RoHS?

The majority of Torque Limiters and Torque Limiter couplings meet RoHS standards; however, some models do not due to inventory adjustments (FIFO: First in, first out.). If it is necessary to meet RoHS standards, please indicate this preference when ordering.

Torq Gards, Torq Gard Couplings

Do the Torque Guards & Torque Guard Couplings conform to RoHS standards?

The TGB, TGX and TGZ series are already compliant. We are now selling off all current non compliant stock of TGM and TGA series, so if you require RoHS compliant products please indicate this when ordering.

What is the allowable temperature range?

-10°C to +100°C.
If the temperature is outside this range, please consult Tsubaki.

What is the life span of the Torque Guards, Torque Guard couplings?

The TGB, TGX, TGZ and TGA series are rated at ten thousand trips, whilst the TGM series is rated at one hundred thousand trips; however, if the machine does not stop tripping then the rating is meaningless. If it trips frequently, the trip torque will gradually decrease, so tighten the adjusting nut or bolts and set screws as necessary.

Can I use the products in an environment where they may be splashed with oil and/or Water?

The TGM series is the sealed type so it excels in environments that are wet, oily or dusty. For other series, it is sometimes possible to upgrade them with these specifications. Please contact TEM for more information

I am currently using a Torque Guard but it won't trip when the machine overloads.

There is a possibility that the adjusting nut has been tightened too much. Excessive tightening eliminates the disk's deflection, causing the Torque Guard to be unable to trip, thus rendering it useless as an overload protection device. Refer to the catalog or manual for nut rotating angles and torque correlation diagrams. Never exceed the allowable torque limit by over-tightening the nut.

I would like to use a Torque Guard coupling for my machine. Does it matter which direction it is installed on the driven or drive sides?

It is possible to install a Torque Guard coupling in either direction. But be aware that the maximum installable shaft diameter is different on the Torque Guard side and coupling side.

I would like to use a high precision TGX with a high-speed shaft, but it cannot stop instantaneously after trip. Is there something you can recommend?

The TGXZ series has non-backlash and complete release features. The TGXZ series is made up of the TGX series (non-backlash) and the TGZ series (complete release). Though it is a special MTO (made to order), it can perform in a number of possible ways. Please contact Tsubaki for more information.

Shock Relay

How does a shock relay work?

A shock relay trips immediately when the motor current exceeds the value set on the relay. It avoids nuisance tripping by presetting the time it begins reading over currents, taking into account start up current. The relay protects not only the sprocket and chain, but also the motor, reducer, and other components affected by overloads