1. General and applicable scope
This standard described the tech requirement, test methods；Inspect rules and market, package, shipment, and storage of the trough idler and plain idler that used in the coal mine well or open-pit mine and coal product grading conditions.
2.Reference （OMIT）
3 tech requirements
3.1 through idler and plain idler should be made according to the described drawings and tech document and comply with MT- 73 and this standard described.
3.2 work conditions
3.2.1 working condition temperature scope:-10℃~+40℃.
3.2.2 air composition should accordance with the requirement of 104th described in “coal mine health and safety rules”
3.2.3 poured water should be allowed in working conditions.
3.2.4 idler should be suit to the fall or cast in the carriage course.
3.3 components requirement
3.3.1 pipe
idler pipe may use metal material or nonmetal material, Its physical performance could not be under of A3 steel, others quality performance data must accordance with commission of related items of this standard.
3.3.2 pillow block （HOUSE）
the pillow block may be made up of cast-iron or stamped iron. Mechanical physical performance of cast-iron could not be under of HT150. Mechanical physical performance of high pressed iron could not be under of 0.8F good quality carbon steel, its named thickness could not less than 3mm.
3.3.3 bearing
The bearing is KA series bearings special for idlers. The dimension data and tech requirement find in attachment A.
3.3.4 Idler shaft
The mechanical Physical performance of shaft should be A3 steel or better. The tolerance of shaft diameter at bearing is js6.
3.3.5 seal equipments
the seal equipment must be of good seal performance and be effective to prevent the water and coal dirt entering into the bearing .
3.3.6 Grease
the quality data of grease that used in idler must according to the described in sheet 1.
| No |
Test item |
Indicate |
l |
Drop point．℃ |
>175 |
2 |
Needle (25℃? 60次)，1/10mm |
265～295 |
3 |
Shear stability ，100 thousands needled |
﹤350 |
4 |
Waterproof ( water10％, Shear ,100 thousands needled) |
﹤375 |
5 |
NaOH％ |
<0．1 |
6 |
Oxygenize stability (100℃、100h、0.78Mpa)，pressure lowed MPa |
<0．35 |
7 |
Impurity substance |
none |
8 |
Shaft anti-rust （51℃，48h,100% humidity ） |
>2级 |
9 |
Relative dampness (-20℃，D=10／s)，P |
﹤15000 |
10 |
lifespan(used in idler bearing)，h |
>20000 |
3.4 assemble requirements
3.4.1 components and (include shopped components) must be inspected and proved qualified before fitted.
3.4.2 tub surface must be clean and its inside surface must paint preservative.
3.4.3 the pillow block and the idler tub must be fitted together strongly and no loosed will be allowed.
3.4.4 the open direction of nylon hold should kept outward when the pillow block fitted in and there should be suit axial chink, completely touch will not be allowed.
3.4.5 the inner seals and outer seals should be fitted individually and the completed seals will not be allowed when the multiple labyrinth seals were used.
3.4.6 the lip damage and lip turnover will not be allowed when the contract seals were used.
3.5 performance requirements
3.5.1 diameter round jump
The diameter round jump could not exceed the data described in sheet 2.
Sheet 2 mm
| Belt speed |
Idler length |
M/s |
<460 |
460~950 |
>950~1600 |
>3.15 |
0.50 |
0.70 |
1.30 |
<3.15 |
0.70 |
1.00 |
1.50 |
3.5.2 axial jump
The axial jump could not exceed 0.7mm on the 500n axial loading rate.
3.5.3 spin resistance.
The spin resistance to the idler could not exceed the data described in sheet 3 in the condition of pressed 2.5n and out linear speed be 2.0m/s.
Sheet 3
| Idler diameter |
Idler length |
Spin resistance |
Φ39~Φ108 |
<460 |
2.5 |
Φ39~Φ108 |
>750~950 |
3.0 |
Φ39~Φ108 |
>1150~1350 |
3.5 |
Φ133 |
>525~600 |
3.0 |
Φ133 |
>790~900 |
3.5 |
Φ159 |
>675~750 |
3.0 |
Φ159 |
>1010~1120 |
3.5 |
3.5.4 fallen strength
3.5.4.1 all the parts and weld beads could not appear broken and damage.
3.5.4.2 the fallen idler’s axial move could not exceed 1.5mm.
3.5.4.3 the fallen idler’s tub and pillow block could not be loose.
3.5.4.4 the fallen idler’s idler resistance could not exceed 1.5 times of the data described in sheet 3.
3.5.5?? axial loading rate
sheet 4
| Idler draft diameter. mm |
Axial loading rate, kN |
Φ89~Φ108 |
10 |
Φ133~Φ159 |
15 |
3.5.6 Sealing performance
3.5.6.1 coal dust seal performance
After running 200 houses at the rate 1450r/min, the coal dust that entered into the bearing grease1 should not exceed 0.8% and the idler should be run normally.
3.5.6.2. Seal performance in the water
After running 24 houses at the rate 1450r/min in the water, the water that entered water should not exceed 150gs.
3.5.6.3 Seal performance in the poured water conditions
After running 120 houses at the rate 1450r/min in the condition of poured water., the water that entered water should not exceed 250gs.
3.5.7 lifespan
The idler reinforcing test service life should not less than 20000h after calculating into actual lifespan.
Note: The grease is general purpose lithium lubricating grease according to GB 7324-94. |
