Product common failure mode
when failure occur,first of all, whether the pulley is flexible or not, whether the bearing is intact or not, whether there is no lag, whether there is tension force in the arm of the tensioner by hand, or not, if there is no fault above, the problem of the tensioner is eliminated. It is necessary to check and analyze the following fault modes:
1. The wrong run of Belt cause abnormal wear and tear on the surface.
Abnormal wear and tear occurred on the surface of the tensioner spring case. Check whether the belt installation direction is wrong or not, causing the belt to contact the tensioner spring case abnormally, and abnormal friction during operation.
2. Improper product installation and adjustment
In view of the type which has been installed both manually and automatically adjusting the tensioner, the tensioning function of the automatic tensioner is not only reflected in its own tension, but also needs to be adjusted by manual adjusting the tensioner's pulley position , and keep the automatic tensioner in working condition. When the automatic tensioner cannot be adjusted to the working angle,the belt tension will not be enough, the engine will produce abnormal noise, belt runout phenomenon.
3. Fracture of tensioner
① Because of wear and tear of belt, the tensioner is instantly returned to zero from the working angle position, and the tensioner and its parts collide violently, which results in the damage and fracture of the tensioner.
② When installing or disassembling the automatic tensioner, the tool is not correct. For example, it must use the square hole of ①5, but the square hole wrench of ①4 is used to slide and rotate to break the tensioner arm, or the rough disassembly, which results in the fracture of the automatic tensioner.
4. The tensioner bias wear
① Due to the poor hole size of the mounting bracket, the automatic tensioner mounting locating pin is forcibly pressed into the bracket pin hole, so that the central bushing of the tensioner and the bushing are abnormally ground.
② The grooved pulley in the wheel train does not match the wedge to cause abnormal bias wear.
5. The arm of the automatic tensioner is too large when idling
① Check whether the belt has become longer or not and more than the maximum tolerance range ± 5 ° of the belt
② If the belt is new, the arm swing still more than the specified requirements, indicating that the work of automatic tensioner is closed to failure.
6. The engine water temperature rises abnormally and causes failure
① The bearing of the pump pulley is ablative, the pump does not rotate.
② The belt is thinned and elongated, and the pulley slips.
③ The torque of the tensioner decreases sharply, resulting in insufficient tensioning force, which makes the belt slip and the wheel train works abnormally.
7. The wheel train has slipping noise and belt fall off
① The belt is used for a long time, the belt lengthened, exceeding the allowable limit tolerance of the belt.
② The automatic tensioner has insufficient tension.
③ Poor alignment of wheel train.
8. The wheel train belt jumps teeth
① First, the wedge of the groove pulley is detected. If the wedge of the groove pulley is too large, it means that the wedge of the groove pulley is too large, causing the belt skipping.
② Remove the damaged belt, measure the belt length, and see if the belt exceeds the tolerance too much, or use the wrong belt.
③ Start the engine, idle speed, and detect the tensioning wheel under the vibration of the crankshaft angle. The range of the automatic tensioning wheel arm swing is within ±5°. It is normal for large diesel engines, if it exceeds, the arm swing is too big. Indicates that the tensioner torque is attenuated, or that the damper is abnormally worn, causing the belt to jump.
Simple fault determination guide
Fault specific analysis process
|
Number |
Failure Mode |
Faults |
Image description |
Check method |
Disposition |
|
1 |
The wrong run of Belt cause abnormal wear and tear on the surface |
Abnormal wear and tear occurred on the surface of the tensioner spring case |
|
Check whether the belt installation direction is wrong or not |
Re-adjust the belt installation direction |
|
2 |
Improper product installation and adjustment |
the belt tension will not be enough, the engine will produce abnormal noise, belt runout phenomenon |
|
1.Is the tensioner in the working corner? 2.Check if the belt is getting longer. 3.Manually adjust whether the tensioner is in the proper position. |
1.Adjust the angle of the tensioner 2.Replace the belt 3.Adjust the position of the manual adjusting tensioner |
|
3 |
Fracture of tensioner |
Fracture of the tension wheel under external force |
|
1.Carefully check the fracture marks, whether there are prying marks or not. |
Replace a new belt and tensioner (it is not the three-pack responsibility) |
|
2. Whether the belt is broken or not, and if so, is it very worn. |
Replace a new belt and tensioner (it is not the three-pack responsibility) |
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|
4 |
The tensioner bias wear |
Is the belt broken, and if so, is wear-out serious. Tensioner eccentric wear, belt trimming |
|
1. Remove the automatic tensioner and check for aluminum or iron chips on the mounting surface of the auto tensioner;Is there any shear trace on the installation pin? |
Adjust the mounting bracket or replace the better mounting bracket |
|
2. Use a special laser tester and a scale seat, respectively placed on the corresponding multi-wedge grooves of the two groove pulleys.Check the amount of displacement of the two corresponding pulleys, if it exceeds 1mm, the belt will cut the glue; then rotate one of the pulley, the other of the pulley will not move, and test the deviation angle of the groove pulley to adjust the position of the corresponding groove pulley. Test as shown |
Re-adjust the wheel train wedge |
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|
5 |
The arm of the automatic tensioner is too large when idling |
The normal range of the arm pendulum is ±5 °, and the engine is allowed to exceed ±5 °at the moment of acceleration, deceleration or loading. |
|
1.Check if the belt is getting longer and exceed the maximum tolerance of the belt. |
Change belt |
|
2.If the belt is new, the arm swing still exceeds the specified requirements, indicating that the work of automatic tensioner is close to failure. |
Replace the tensioner |
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|
6 |
The engine water temperature rises abnormally and causes failure |
The engine water temperature shows an abnormal rise |
|
1.Turn the water pump pulley by hand to check if there is any stagnation in its rotation. |
Replace the pump pulley |
|
2. Check whether the belt is longer and broken or not |
Replace belt |
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3. Use the torque wrench with watch to check if the tensioner has a tightening force |
Replace the tensioner |
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|
4. Detect whether other accessory pulleys are not rotating properly, abnormal noise, stuck or locked; whether the pulley is damaged or abnormally worn |
Related attachments |
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|
7 |
The wheel train has slipping noise and belt fall off. |
The pulley belt noise is abnormal |
|
1.Start the engine, water the belt, and wet the belt groove surface. If the noise is increased, as the water evaporates, the noise gradually returns to the previous level, indicating that the belt is slipping. Visually inspect the belt for wear and see if the tensioner arm is in the free position. If the belt wear is thinner or the tensioner arm is in the free position, replace the new belt. |
Replace belt |
|
2.If the belt is worn and the tensioner arm is far away from the free position (usually 25-35 degrees of angular difference from the free position), replace the tensioner. |
Replace the tensioner |
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3.If the noise is weakened or disappeared, the noise will return to the previous level as the water evaporates, indicating that the pulley is not coplanar and the wear of the wedge surface is generated when the belt enters the groove (ie, the pulley alignment is not aligned). |
Adjust alignment |
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|
8 |
The wheel train belt jumps teeth |
PK with glue or jump out of the V-groove |
|
1.First, the wedge of the groove pulley is detected. If the wedge of the groove pulley is too large, it means that the wedge of the groove pulley is too large, causing the belt skipping. |
Adjust the pitch of the groove pulley, replace the belt, and automatically tensioner |
|
2.Remove the damaged belt, measure the belt length, and see if the belt exceeds the tolerance too much, or use the wrong belt. |
Replace belt |
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|
3.Start the engine, idle speed, and detect the tensioning wheel under the vibration of the crankshaft angle. The range of the automatic tensioning wheel arm swing is within ±5°. It is normal for large diesel engines, if it exceeds, the arm swing is too big. Indicates that the tensioner torque is attenuated, or that the damper is abnormally worn, causing the belt to jump. |
Replace the tensioner |
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