For the Finishing Mill of a hot strip mill, the input shaft of several different gearboxes are each driven by a DC motor of 10,500 HP operating at 125 RPM PROJECT REQUIREMENTS: For your ASSIGNED gearbox only, you are required to analyze the gearbox capabilities by doing the following: 1. Calculate the maximum motor torque 2. calculate the force transmitted by the gearing. 3. Using statics, calculate the equivalent radial load at the bearings for BOTH the pinion shaft and the gear shaft. (Four bearings total; two per shaft). Include FBDs of the shafts. 4. Research the load capacities for the bearings. (Hint: the bearing manufacturer is most likely Timken / Torrington). Calculate the expected bearing life for each bearing. Calculate the safety factor for both the bending strength and the pitting resistance for the pinion shaft AND the gear shaft gear teeth based on the transmitted load and the gear material(s). 7. Draw the shear, bending moment, and torque diagrams for the GEAR SHAFT ONLY. Calculate the torsional shear stress and bending stress at three points on the output side of the shaft: the point of maximum load, the roll body fillet and the roller bearing shoulder. Include any stress concentration factors from the geometry. 8. 5. 6. 4 "BOSTS TAPERED ROLLER BRES TYPE TOO EE 843220- 432100 229 15 4-11% TO END OF SHAFT 1-t 8- BOLTS 91719 8-14 BOLTS 8-43 'FON. BOLTS to in 18 MOTOR PINION 38.415 PD-LISEDP MILL TOOTH FORM DOUBLE RELICAL. STAGGERE O Sahas 34705-AP GASKET 8-15 STUD BOLTS 8-1 BOLTS 22°57′47 HELIX ANGLE FACE-56 EFFECTIVE FACE HOLO 24705 AN 84105-AJ 84705.U SEAL 125/295 RPH 2-43 2-5 O 322 DIA 23 DIA 19° RON IRIA 9:5" Ⓡ BROS 191729-7 91729-E TSEAL 1x³ sette 91719-T 44,000* 9FT21-E+H 16% 91729.V 92150-B 2²-8" 12"-3" 84705 AB 24.995 1202 DIA 28 D Ⓡ GEAR 251 29.000 BHOJDIA 322 DIA *O THE TAPERED ROLLER BRG. TYPE TPO LM 772748 ♣ LM 772 710 DC 194*¹×24,995** 7% + 5.8° 96.45/287.62 RP ir· 6-12PXLTS 8-1-STUD BOLTS 91719-W 2-9¹½2 B T 91721-F. BEAR 49.585 P.D.-1.158 D.P MILL TOOTH FORM DOUELE HELICAL STAGGERED TEETH5 23 57′47″N HELIX ANSLE 57 TEETH 61 FACE-56 EFFECTIVE FACE 18⁰ 15 8-1 STUD BOLTS 8 BOLTS 84705 AP GASKET 84705-AR 84105-AS 84705-AT SEAL DRIVE CPLG. 12 NO 20 HO FLOAT SHAPT CPLG.... 92148-A 92146-B WITH DRIVE COUPLING REMOVED (B) TAPERED BOLLER BEG TYPE TOOEE 843220-843291 DC 22 29 77 45/4 MACHINE FINISH MARK VALU 92149-A /92145-Sec. 21" $2140-E &-BOLTS sy 0 3:5 8-12 STUD BOLTS T f 1 1 PP Frr 10 FOR ALLOWE p 4632 63 125 250 500 REVISIONS CHIC DATE A TOOTH DATA REVISED NOS/25/20 BOTH DeadOnSeray based 2-19-45 ERGATION A C3 WAS 3 IN TYR SECTION an Airles DSTAGGORE-TERTH SHOWN E WAS & HOLES 19 VA 2²44 12 H 84705 AM TYPICAL SECTION AT BEARING CAP SEAL -SCALE LO V₂ KEHID 600 42% SCALE 2/ DWN. BY VAS CAPA CH'KD. BY HD.C DATE 11-18-644 1,21 6 BRG 49.585 2-9 30% THIS PRINT INDICATES OUR IDEAS. IT IS LOANED SUBJECT TO RETURN ON DEMAND, AND UPON THE EXPRESS CONDITION THAT IT WILL NOT WE USED DIRECTLY OR INDIRECTLY IN ANY WAY BETRIMENTAL TO OUR INTEREST. SINGLE REDUCTION DRIVE GENERAL ARRANGEMENT FOR STAND NO. F3 BLAW-KNOX COMPANY FOUNDRY & MILL MACHINERY GROUP PITTSBURGH, PENNSYLVANIA SECTION X-X-X-X D 13 18 14 15 171 5-7 17 10 SI FACE 3-8 2-9 301 6 6 244 REVISIONS DESCRIPTION MOTOR STD F3 10,500 92147.8 10" 84705-MM MARK REGD BATE BY CHK MADE BY 3:3 CHECKED BY 211 TAPERED ROLLER BRGY TYPE YDO EE 843220- 843291 DC-22 20-778 453° 84705-45 22140-D MILL SPEED WORK RPM RATIO RPM 125/295 1.296/1727.62 169.84 28' 96,45 TOT.56 18-coeurs 8-12 STUD BOLTS 04705 AT SEAL 84705-AR 84705-AP GASKET N⁹ 20 H.D. FLEX.CPLG. MALE HALF DESCRIPTION AFPRO. No. PM ROLL DIA BILL OF MATERIAL. 24 HOT STRIP MILL SHOP GAD. NO. $33.495. HDC SCALE DATK DESIGN APPROVAL REMARKA GS-70113
For the Finishing Mill of a hot strip mill, the input shaft of several different gearboxes are each driven by a DC motor of 10,500 HP operating at 125 RPM.
For your ASSIGNED gearbox only, you are required to analyze the gearbox capabilities by doing the
following:
1. Calculate the maximum motor torque
2. calculate the force transmitted by the gearing.
3. Using statics, calculate the equivalent radial load at the bearings for BOTH the pinion shaft and the gear shaft. (Four bearings total; two per shaft). Include FBDs of the shafts.
4. Research the load capacities for the bearings.
(Hint: the bearing manufacturer is most likely Timken / Torrington).
5. Calculate the expected bearing life for each bearing.
6. Calculate the safety factor for both the bending strength and the pitting resistance for the pinion shaft AND the gear shaft gear teeth based on the transmitted load and the gear material(s).
7. Draw the shear, bending moment, and torque diagrams for the GEAR SHAFT ONLY.
8. Calculate the torsional shear stress and bending stress at three points on the output side of the shaft: the point of maximum load, the roll body fillet and the roller bearing shoulder. Include any
stress concentration factors from the geometry.
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