Troubleshooting  Roller Chain Drive Troubleshooting

Perform the following measures or replace with a new product when your roller chain or sprocket suffer severe damage or breakage.

General

1 Chain is riding up on the sprocket
2 Unusual noises
3 Excessive vibrations in chain
4 Chain winds up on the sprocket (poor separation from the sprocket teeth)
5 Rusting of the chain
6 Excessive wear on the inside surface of the links plates and sides of the sprocket teeth
7 Excessive wear on the link plate side surfaces and pin heads
8 Improper flex or bending of chain, tight joints
9 Spreading of link plates

Plate related

10 Breakage of link plate
11 Cracks form in the link plate (fatigue) that are perpendicular to the direction of pull
12 Deformation of link plate holes
13 Corrosion stress cracks appear (bow-shaped cracks in the link plate)

Pin related

14 Breakage of pin
15 Pin rotates or begins to protrude
16 Wear or rust occurs on the connecting pin only in a lifting application or similar operation

Bush/roller related

17 Roller and/or bush cracks (falls off)
18 Roller does not rotate
19 Roller is opening up
20 Roller is becoming hourglass shaped
 Answers

General

1
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Chain is riding up on the sprocket
Cause 1 Roller chain and sprocket do not match Solution Replace the roller chain or sprocket with one that is the correct size.
Cause 2 Excessive load Solution Reduce the load (lubricating to the driven machine is also effective). Or increase the number of or size of chains.
Cause 3 Elongation of the chain due to wear or excessively worn sprocket teeth Solution Replace with new chain or sprocket
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2 Unusual noises
Cause 1 Improper installation of the sprocket or shaft Solution Inspect and correct
Cause 2 Chain casing or bearings are loose Solution Tighten all nuts and bolts
Cause 3 Excessive or insufficient slack in the chain Solution Adjust the distance between shafts to obtain the proper amount of slack
Cause 4 Excessively worn chain or sprocket Solution Replace the chain and sprocket with new ones
Cause 5 Lack of or unsuitable lubrication Solution Provide proper lubrication according to the operating conditions
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3 Excessive vibrations in chain
Cause 1

Chain is resonating with periodic external force


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Solution

Change the chain's mode of vibration

1. Preventing resonance

a. Change the natural frequency of the chain

○Alter the effective tension either by applying an initial tension or adjusting the existing one

○Install a tensioner to change the chain span

○Replace the chain. Choose a different mass and spring coefficient

b. Change the vibration frequency

○Change the sprocket rotational speed

○Re-evaluate the device set-up

2. Mechanically reducing the vibrations

○Install a guide stopper

○Install a self-adjusting tensioner on the slack side.


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Cause 2 Load fluctuations are excessively large Solution Reduce fluctuations with a fluid coupling, etc.
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4
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Chain winds up on the sprocket (poor separation from the sprocket teeth)
Cause 1 Span between shafts is too large Solution Install an idler
Cause 2 Excessive slack in the chain Solution Adjust the chain length or distance between shafts
Install a tensioner
Cause 3 Elongation of the chain due to chain wear or excessively worn sprocket teeth Solution Replace with new chain or sprocket
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5 Rusting of the chain
Cause 1 Improper lubrication or poor environment Solution Replace chain and protect it from the environment with a chain casing or proper lubrication
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6 Excessive wear on the inside surface of the links plates and sides of the sprocket teeth
Cause 1

Improper installation


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Solution Correct sprocket and shaft installation
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7 Excessive wear on the link plate side surfaces and pin heads
Cause 1

Improper installation of guides, etc.


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Solution Check the condition of the guides, and increase the gap between the guides and the chain.
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8
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Improper flex or bending of chain, tight joints
Cause 1 Deformation of chain due to inproper installation Solution Inspect the installation and correct as necessary
Cause 2 Contamination from wear dust or dirt due to improper lubrication (grease, etc.) Solution Remove the chain, clean it thoroughly, and provide proper lubrication
Cause 3 Excessive load, bent pin, bush cracking Solution Reduce the load or increase the number of or size of chains.
Cause 4 Corrosion or rusting Solution Install a chain casing to protect the chain
Cause 5 Seizing from improper lubrication Solution Provide proper lubrication according to the operating conditions
Cause 6

Seizing of pin and bush


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Pin and bush seize from high-speed operation, causing poor articulation and possibly leading to chain breakage

Solution Provide the proper operating conditions
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9 Spreading of link plates
Cause 1

Uneven or excessive loading caused by improper installation


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Solution Replace with new chain and correct installation
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Plate related

10
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1. Static fracture

Pulling a link plate with a tensile load beyond its breaking load will cause it to stretch and then break


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2. Fatigue fracture

By repeatedly applying a load past its fatigue limit (fatigue strength), the fatigue will start at the holes and then cause sudden chain breakage


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3. Offset link plate fatigue

Offset link plates are bent at the center, and the resulting concentration of stress at the bend can cause a fatigue break. Avoid using offset links in high-stress applications.

Cause 1 Excessively large shock load Solution Reduce shock loads by making the start-up, stopping, and other actions smoother (by installing a shock absorber, etc.).
Increase the size or number of chains.
Cause 2 Vibration in the chain Solution Install an anti-vibration device (for example, a tensioner or idler sprocket).
Refer to the section on "Excessive vibration in chain."
Cause 3 Large inertia in the driven machine (excessive load) Solution Reselect chain, or alternatively increase the size or number of chains.
Cause 4 Corrosion Solution Replace with a new chain. Install a casing to protect the chain. Periodically clean and lubricate the chain.
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11 Cracks form in the link plate (fatigue) that are perpendicular to the direction of pull
Cause 1 Loads are greater than the maximum allowable load Solution Remove all large or excessively repeating loads. Increase the size or number of chains.
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12
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Deformation of link plate holes
Cause 1 Overload Solution Remove the cause of the excessive load and replace with a new chain.
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13
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Corrosion stress cracks appear (bow-shaped cracks in the link plate)
Cause 1 The chain is being used in an acidic or alkaline environment.
(This is not caused by a repetitive load.)
Solution Replace with a new chain. Install a casing to protect the chain.
Consider a chain with a high resistance to corrosion stress cracking. (Contact a Tsubaki representative for more information.)
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Pin related

14
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1. Static fracture

The type of fracture found when subjecting the chain to breakage tests.
Occurs when the chain is subjected to a load greater than its breakage strength.


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2. Fatigue fracture

Occurs when the pin is repetitively subjected to loads greater than its fatigue limit. Re-check the size of the peak load and formulate a countermeasure.


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3. Shock-induced bending fracture

The pin is subjected to a large shock load and breaks. The origin side receives the tensile load, and the fracture progresses from an origin point. A pin is especially susceptible to becoming weak with regard to bending when the surface of the pin has cor

Cause 1 Excessively large shock load Solution Reduce shock loads by making the start-up, stopping, and other actions smoother.
Cause 2 Pin subjected to a repetitive load greater than its fatigue limit Solution Remove the excessively large repetitive load. Increase the size or number of chains.
Cause 3 Corrosion Solution Install a casing, and periodically clean and lubricate the chain.
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15
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Deformation of link plate holes
Cause 1 Excessive load or improper lubrication Solution Replace with new chain. Improve the lubrication or loading conditions.
Cause 2 Operating a chain at high load without proper lubrication can create friction between the pin and bush, causing the pin to rotate. In this situation, the pin may come out, leading to chain breakage. Solution Replace with new chain immediately. Do not weld or reuse the pins. (Dispose of the old chain to be sure that it is not used again by mistake.) Also, if the pin head of link plate surface is worn, check the installation.
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16 Wear or rust occurs on the connecting pin only in a lifting application or similar operation
Cause 1 Improper initial lubrication during installation Solution Replace the connecting link. If pin wear is excessive, replace the chain also.
Take special care to properly install the connecting section for devices such as end brackets used for lifting applications, etc.
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Bush/roller related

17
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Fatigue breakage

Reached its fatigue limits during operation and eventually fractured. Occurs when the chain impacts the sprocket teeth with a force exceeding the chain's kilowatt ratings.

Cause 1 Excessive load or rotational speed Solution Reselect chain according to the kilowatt ratings tables
Cause 2 Inadequate lubrication Solution Replace the chain. Provide adequate lubrication according to the operating conditions
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18 Roller does not rotate
Cause 1 RS11-SS-1、RS15-1、RS25-1、RS35-1 Solution A bushed chain instead of a roller chain is being used
Cause 2 The inner plate is moving inward, or the bush is cracked Solution Replace the chain. Re-inspect the installation and load conditions
Cause 3 Foreign matter has gotten between the bush and roller Solution Periodically clean the chain. Install a casing to protect the chain.
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19 Roller is opening up
Cause 1

Overload


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Solution Reduce the load, and provide adequate lubrication
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20 Roller is becoming hourglass shaped
Cause 1 Excessive load or inadequate lubrication Solution Replace with new chain. Improve the lubrication or loading conditions.
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