Troubleshooting　Large size conveyor chain

General

1The chain rides up onto the sprocket
2The chain gets wrapped around the sprocket (it is difficult to disengage).
3There is a strange noise.
4The inside of the chain plates or the flanks of the sprocket teeth are worn.
5Wear of sprocket tooth root and tooth bearing surface
6Poor articulation
7The chain sticks and slips (stick-slip phenomenon).
8One of the Inner link or pins of an NF block chain or BF chain (without rollers) wears out.
9Chain rust
10Wear caused by transported items
11Corrosion wear
12Electrochemical corrosion

Plate related

13Rapid plate fracture
14Deformed plate holes, pin rotation (pin is out of position)
15Cracks appear in the plate (1) Fatigue failure
16Cracks appear on the plate (2) Stress corrosion cracking
17Red patterns are visible on the plate

Pin Related

18(1) Fatigue failure of the pin
19(2) Corrosion fatigue of pins
20(3) Brittle fracture of the pin
21(4) Rapid pin destruction

Bush and roller related

22Roller rotation failure Roller is unevenly worn
23The roller opens.
24Rollers and bushings break.
25The rollers wear out in a drum shape.
To the answer

General

1


[Click to enlarge]

The chain rides up onto the sprocket

Cause 1 Chain and sprocket are not compatible Solution Replace the chain or sprocket with the correct size. Install a tensioner.
Cause 2 Insufficient winding angle Solution The winding angle shall be 3 teeth or more.
Cause 3 Significant overload Solution Reduce the load (e.g., by adding a shock absorber).
Cause 4 Insufficient back tension Solution Adjust the catenary, take-up, and install the tensioner.
Cause 5 The chain is worn and stretched. Solution Replace with a new chain.
Cause 6 The center distance between the chain and sprocket is not compatible. S≠S' Solution After inspection, make corrections.
Return to list
2The chain gets wrapped around the sprocket (it is difficult to disengage).
Cause 1 There is too much chain slack. Solution Adjust the chain length or center distance, or install a tensioner.
Cause 2 Sprocket wear Chain and sprocket mismatch Solution Replace the chain and sprockets with new ones.
Return to list
3There is a strange noise.
Cause 1 Insufficient oil supply to the sliding parts of the pin/bush Solution Lubricate sufficiently.
Cause 2 Insufficient oil supply to the bushing/roller sliding area Solution Use bearing rollers and Plastic Roller.
Cause 3 Entanglement and running over Solution As mentioned above
Cause 4 Loose chain casing or bearing Solution Retighten all bolts and nuts.
Cause 5 Interference between the chain or moving part and the casing Solution After inspection, make corrections.
Cause 6 Significant wear on the chain or sprockets Solution Replace the chain or sprockets (replace the entire chain).
Cause 7

Guide channel setting error


[Click to enlarge]

 Solution After inspection, make corrections.
Return to list
4


[Click to enlarge]

The inside of the chain plates or the flanks of the sprocket teeth are worn.

Cause 1 Sprocket misalignment Solution Remove the chain and correct the centering of the drive and driven sprockets.
Cause 2 The chain is pushed sideways. Solution Eliminate the cause of the pressure. Use guide rollers.
Cause 3 Runout due to poor machining accuracy of sprocket shaft hole Solution After checking for defects, correct them and replace with a new sprocket.
Return to list
5Wear of sprocket tooth root and tooth bearing surface
Cause 1 Chain wear Solution Replace the chain and sprockets at the same time.
Cause 2 Insufficient number of meshing teeth Solution Increase the number of teeth on the sprocket.
Cause 3 Uses BF chain (without rollers) Solution Change to RF chain (with rollers).
Cause 4 Wear inclusions and insufficient hardness of the teeth against excessive load Solution Use hardened tooth tips or block replacement teeth.
Cause 5 Incompatible sprocket and chain Solution Replace the chain or sprocket with the correct size.
Return to list
6Poor articulation
Cause 1 Rusty and corroded Solution
  • - Add a partition to protect the chain.
  • - Select the appropriate specifications (GS, etc.).
Cause 2 The conveyed object is stuck between the pin/bush/plate, or foreign matter gets in. Solution
  • - Add a partition to protect the chain.
  • - Use a larger specification for the gap between the pin, bushing, and plate.
  • - Remove or apply highly penetrating oil.
Cause 3 Chain deformation due to improper installation Solution Check and correct the installation of the sprocket and shaft.
Cause 4 Insufficient lubrication Solution Consider using oil or wear-resistant specifications (CT, BT Series, etc.).
Cause 5 Use at high temperatures (over 400°C) Solution Use a chain with the appropriate clearance.
Cause 6 Burnout due to overload Solution Reduce the load. Oil regularly (for example, by installing an oiling device).
Cause 7 Pin bending due to severe overload Solution Reduce the load. Oil regularly (for example, by installing an oiling device).
Return to list
7The chain sticks and slips (stick-slip phenomenon).
Cause 1 Change the chain's rolling friction coefficient. Solution
  • ・Clean and lubricate the moving parts. Apply Tsubaki Shakuri-less Oil.
    (・Please inquire about Tsubaki Shakuri-less Oil)
  • ・Replace the sprocket with a new one.
  • - Use Bearing Roller Conveyor Chain.
Cause 2 It's slow. Solution Make it faster than it is now.
Cause 3 The frame is not rigid enough, and the chain is small compared to the device. Solution
  • -Improved frame rigidity and increased chain model number.
  • - Reduce slack in the drive roller chain.
Cause 4 Increased friction Solution
  • - Oil is applied between guide channel and chain to reduce friction.
  • - Use Bearing Roller Conveyor Chain.
Cause 5 conveyor length is long. Solution Divide the conveyor to shorten conveyor length.
Cause 6 Speed fluctuation due to polygonal movement Solution The number of teeth on the drive sprocket must be 12T or more.
Return to list
8One of the Inner link or pins of an NF block chain or BF chain (without rollers) wears out.
Cause 1 Internal tension increases when meshing with the sprocket. Solution
  • - Make the sprocket with pieces.
  • ・Reduce the load.
    Lubricate both the chain and the sprockets.


[Click to enlarge]
Return to list
9Chain rust
Cause 1 Inappropriate material selection Solution Replace the chain. Protect from the atmosphere. Apply anti-rust agent. (Oil, cover)
Cause 2 condensation Solution Eliminate the temperature difference between the inside and outside of the conveyor (using heat insulation, etc.). Install a drain to remove water.
Return to list
10


[Click to enlarge]

Wear caused by transported items

Cause 1 Abrasive materials such as ore powder can adhere to the chain, causing wear on the chain surface. Solution
  • - Ensure that the transported item does not get caught on the chain.
  • - The chain is made wear-resistant.

    →Please contact us.
Return to list
11


[Click to enlarge]

Corrosion wear

Cause 1 Acidic and alkaline liquids cause corrosion, and mechanical wear is also added to this, accelerating wear. Solution
  • - Use chemical-resistant materials that are not affected by chemicals.
  • - Use wear-resistant materials for parts that are subject to mechanical wear.

    →Please contact us.
Return to list
12


[Click to enlarge]

Electrochemical corrosion

Cause 1 When a chain is covered with water or passes through a solution, the sliding parts of the chain form a local battery, causing galvanic corrosion of the surface. Solution
  • - Use chemical-resistant materials that are not affected by chemicals.
  • - Use wear-resistant materials for parts that are subject to mechanical wear.

    →Please contact us.
Return to list

Plate related

13Rapid plate fracture
Cause 1 Excessive load, excessive take-up tension Solution
  • - Remove causes of overloading and overcharging.
  • - Install safety devices (such as Tsubaki Shock Relay).
  • ・Increase the size (size up).
Cause 2 Strength reduction due to wear and corrosion Solution
  • ・Replace with a new one. Protect the conveyor chain by attaching a cover.
  • - Regularly oil (grease).
  • - Select the appropriate chain specifications.
Cause 3

The plate is pushed up by the teeth of the sprocket.


[Click to enlarge]

 Solution
  • - Check and correct installation accuracy.
  • - Check for wear on the chain or sprocket, then repair or replace it.
  • - Check and correct any mismatch between the chain and sprocket.
Return to list
14Deformed plate holes, pin rotation (pin is out of position)
Cause 1 overload Solution
  • - Excluding factors related to overload.
  • ・Increase the size (size up).
Cause 2 Improper assembly of connecting link Solution Replace the joint with a new one.
Cause 3 Overload and poor lubrication Solution Replace with a new one. Improve overload and oil supply.
Cause 4 Sticking between pin and bush, poor bending Solution
  • ・Increase the size (size up).
  • - Use a chain with a larger clearance between the pin and bushing.
  • ・Oil supply between pin and bush (highly penetrating lubricant)
Return to list
15


[Click to enlarge]

Cracks appear in the plate (1) Fatigue failure

Cause 1 Overload, excessive tension on take-up, excessive repeated load Solution Excluding overload and excessive repeated load.
Cause 2 A load exceeding Maximum allowable load is applied. Solution
  • - Increase the size (size up), or improve the specifications to increase Maximum allowable load.
  • ・Replace with a new one.
Cause 3 Repeated loads are applied to the attachment Solution
  • - Excludes overloads and excessive repeated loads.
  • - Increase allowable load of the attachment by increasing the size of the chain, etc.
Return to list
16


[Click to enlarge]

Cracks appear on the plate (2) Stress corrosion cracking

Cause 1 Use in acidic or alkaline environments
Not the effect of repeated loading		 Solution
  • ・Protect the chain from the elements with a cover or replace it with a new one.
  • - Uses specifications that are highly resistant to stress corrosion cracking.
Return to list
17Red patterns are visible on the plate
Cause 1 Scale adhering to the plate material Solution
  • ・You can continue to use it (DT, DTA, AT, etc.).
Return to list

Pin Related

18


[Click to enlarge]

(1) Fatigue failure of the pin

Cause 1

If a load exceeding Maximum allowable load is repeatedly applied, the pin may be subject to fatigue failure.

The peak load acts as a cyclic load on the chain.

 Solution
  • - Check the magnitude of the peak load and eliminate the cause.
  • -Replace with a chain of larger size (pin diameter).
Return to list
19(2) Corrosion fatigue of pins
Cause 1

The side with the pit is subjected to a tensile load, causing destruction to progress from the pit.

In particular, if the surface of the pin is corroded, it becomes weak against bending, making this phenomenon more likely to occur.

 Solution
  • ・As with "Plate related > Cracks appear on plates > (2) Stress corrosion cracking," protect the chain with a cover or similar.
  • - Use corrosion-resistant pin material (MT, etc.).
Return to list
20(3) Brittle fracture of the pin
Cause 1

Environmental factors

 Solution
  • - Change to corrosion-resistant specifications.
Return to list
21(4) Rapid pin destruction
Cause 1

overload

 Solution
  • ・Increase the size (size up).
Return to list

Roller Bush Relationship

22Roller rotation failure Roller is unevenly worn
Cause 1

Roller load is excessive

 Solution Use proper lubrication between bushings and rollers and appropriate specifications (DTA, bearing rollers, etc.).
Cause 2

Conveyed objects and foreign matter get between the bush and roller.

 Solution Remove regularly and install a partition to protect the chain.
Cause 3

Transported materials and foreign matter accumulate on the rails

 Solution Regularly remove the waste and install partitions to prevent accumulation.
Cause 4

Lubricant does not get between the bush and roller or between the roller and plate
Adheres to the roller surface and rail

 Solution Select the appropriate lubricant and lubrication method.
Cause 5

Rusted bushings and rollers

 Solution Select the appropriate specifications (RT, etc.).
Cause 6

The inner plate moves inward.

 Solution Replace, re-inspect installation, and check load.
Cause 7

Bush crack

 Solution Reduce the load and reduce the rotation speed.
Cause 8

Contact between roller side and plate side due to thrust load

 Solution Excluding thrust load factors.
Cause 9

Incompatible chains and sprockets, worn teeth

 Solution Check the tooth profile.
Return to list
23The roller opens.
Cause 1

Overload, excessive take-up tension

 Solution Reduce the load, lubricate properly, and remove excessive rail steps. Loosen the take-up.
Return to list
24Rollers and bushings break.
Cause 1

Overload, excessive take-up tension

 Solution Reduce the load. Properly lubricate. Loosen the take-up.
Cause 2

Too few teeth for the speed.

 Solution Increase the number of teeth. Reduce the speed.
Return to list
25The rollers wear out in a drum shape.
Cause 1

Overloaded or under-lubricated

 Solution Check for overload or improve oil supply, or replace the chain with a new one.
Cause 2

Rail wear

 Solution Repair or replace rails.
Return to list