Reductorul Proiect Om

1. STRUCTURE, SCHEME, TORQUES AND ROTATIONS FOR EACH SHAFT.

M = electrical motorP = power at the motorn = rational speed of the motor shaftMtm = nominal torque at the motor shaftic = transmission reactionI = input shaftII = output shaftnI = rotational speed of the imput shaftnII = rotational speed of the output shaftII = torque at the imput shaftIII = torque at the output shaftir = speed reducers ratiou = gears ratio1 = driver wheel pignon2 = driver wheelA, B, C, D = bearings

IMPUT DATA:

P = 3 kwn = 1450 rot/minic = 1,37u = 2,8Lh = 9000 h

Motor’s shaft

INPUT SHAFT

o Rotational speed

o Torque

OUTPUT SHAFT

o Rotational speed

o Torque

2. PREDIMENSIONING OF THE GEAR

Nr Parameter Calculus

0 1 2

1. Input data1.1 Rotational speed of the

pinion n1=1058,39 rot/min

1.2 The pinion’s torque TI = 27069,31034N•mm

1.3 Gear ratio udat= 2,8

1.4The imposed lifetime

Lh= 9000 h

1.5

Functioning conditions

Driver machines: electrical motorDriver machines: shocks

Examples:-Electrical Generators: uniform shocks

-Elevator: small shocks-Lifting Machines: medium shocks

-Mill: big shocks1.6

Stresses cyclesContact pulsatoryBending pulsatory

1.7 Number of loading cycles for one complete rotation

of the pignon and of the driven wheel

1=1

2=11.8

The profile of the reference rack

For oblique teeth:αn=20° h*an=1

C*an=0,25

3.3.2 Contact factor

3.3.3 Zε cover degree factor and εα= 1,4 for oblique teeth

3.3.4 Helix angle factor Zβ

3.4 The bending factor calculus3.4.1 Number of

the teeth of the equivalent wheels

3.4.2 Profile displacement in normal plan coefficient

xn1,2= 0

3.4.3 Teeth shape factors

YFa1,2= YFa (zn1,2,x n1,2)YFa1=2,66YFa2=2,24

3.4.4 Tension correction factors at the base of the teeth

YSa1,2= YSa (zn1,2,x n1,2)YSa1=1,58YSa2=1,74

3.4.5 Yε ,cover degree factor

3.4.6 Tooth inclination factor Yβ

3.5 Loading correction factors3.5.1 Functioning

regim factorKA= 1,1

3.5.2 Dynamic factor

Kv= 1,05...1,10 it is adopted 1,08

2. Choosing of the materials of the plate treatments and of the limitations2.1 Choosing

of the materials of the plate treatments and obtained hardness

It’s chosen carburizing steels

17 CrNi 16 60 HRC 350....450 HB σ02= 685 MPa σr= 1000 MPa

2.2 Limit stresses contact and bending

σH lim 1,2 = 1500 Mpa - contact

σF lim 1,2 = 500 Mpa - bending

3. Predimensioning calculus3.1

Number of the teeth of the pignon (z1) and number of the teeth of the driven wheel (z2)

for carburising wheels, is adopted 45˚

= 6°…14°for carburised wheels, is adopted 10˚

z1 = z1max

and z1 є N for wheels carburized and/or hardenedz2= z1 • udat= 23 • 2,8= 64,4 and z2 є N

3.2

Real gear ratio 0,007 ≤ 0,03

3.3 Factors for contact calculus3.3.1

Elasticity factor of the material of the wheels

for rolled steels v1=v2=0,3 and E1=E2=2,06•105 MPa

ZE= 189,8 √MPa

3.5.3 Face load factor KHβ= 1,3...1,75 is adopted 1,4

KFβ= 1,25...1,7 is adopted 1,43.5.4 Transverse

load factorfor oblique teeth

KHα= KFα= 1,4435KHα for contactKFα for bending

3.6 Allowable strength for

contact loading

and

for loading stress

ZL ZV ZR= 1,0

ZW= 1 ZX= 1

ZN1 =1,03 ZN2 =1,1

NL1=60 n1Lh1 =60∙1058,39∙9000∙1=5,715•108

NL2=60 n2Lh2 =60∙377,996∙9000∙1=2,041•108

SHmin=1,1

3.7 Predimensioning of the distance between axis3.7.1 Width

coefficientPreliminary ψa=0,30

Final

3.7.2 Centre distance

3.7.3 The distance between axis from the strength

- number of teeth of driven wheel

- the gear ratio

4. DIMENSIONING AND CHEAKING CALCULUS

4.1 The distance between the reference axes

3. GEARS GEOMETRICAL ELEMENTS CALCULUSCHOOSING OF THE COEFFICIENT OF PROFILE DISPLACEMENT

3.1 Pressure angle in frontal

3.2 The real angle of gearing in frontal plane, and in normal plane

4. GEOMETRIC ELEMENTS OF THE WHEELS

4.1 The driving circle’s diameters

4.2 Base circles diameters

4.3 Rolling circles diameters

4.4 Adendum circles diameters

4.5 Dedendum circles diameters

4.6 The pressure angle on the adendum circle

4.7 Inclining angle of the teeth on the base circle

4.8 Inclining angle of the teeth on the adendum circle

4.9 The pitch on the base circle in frontal plane

4.10 The tooth’s arc in the normal plane(n) and the frontal plane(t), mm4.10.1 On the diving

circle

4.10.2 On the hed circle

5.Equivalent wheels and equivalent gearing elements5.1 Number of

teeth of equivalent wheels

5.2 Divisation circles diameters of the equivalent wheel

5.3 Base circles diameters of the equivalent wheel

5.4 Adendum circles diameters of equvalent wheel

5.5 The distance between the equivalent gearing’s axis

5.6 Coovering of the equivalent gearing

6. verification of functional-construction conditions6.1 Coverage of

gear

6.2 condition to avoid tooth sharpness

6.3 provided to avoid interference

4. PREDIMENSIONING CALCULUS

Imput shaft, dI

Output shaft, dII

5. GEAR FORCES CALCULUS

5.1 Calculus forces

- Tangential force

- Radial force

- Axial force

5.2 Calculus scheme and establish of forces direction

6. SHAFT CALCULUS

6.1 Predimensioning calculus

Imput shaft, dI

Output shaft, dII

6.2 Choose of the bearing mountings

X= 0,4 d=dI,II – (4...8) mm

Table 6.1

Series d D B a Cr e Y Cor

I 30305 25 62 17 13 44600 0,30 2 43000II 30308 40 90 23 19 85800 0,35 1,7 95000

MiH

[H]

MiV

[V]

Calculus of the reaction forces

ΣH MiB= 0

Stresses calculus :

Compression

Torsion

Bending

7. KEY ASSEMBLING

From STAS 1004 we choose,

b = 12 mmh = 8 mm

dII b h12......17 5 517......22 6 6

22......30 8 830......38 10 838......44 12 844......50 14 950......58 16 1058......65 18 11

lstas 140 125 110 100 90 80 70 63 56 50 45 40 36 32 28 25 22 20

8. CHECK OF THE BEARING MOUNTING FOR THE INPUT SHAFT

Dinamic loading capacity, Cmec

Durability, LEquivalent dynamic load, P

9. CHOOSING AND JUSTIFYING THE OILING SYSTEM AND SEALING SYSTEM

Oiling the gearings:

The gears from speed reducers are grease through splashing in the oil bath. For this aim in which a gear from the gearing mechanism is introduce in the oil bath until a tooth is covered with oil, not more than 10 mm, and without passing six time the modulus.In case of speed reducers with more steps (when the wheels don’t reach the bath), the grease is made with a parasite gear, or with the help of some discs or splashing spoons.The grease through splashing is applied on gearing mechanisms that are working periodically, with speeds up to 15m/s. For greater peripheral speeds, the grease is done with oil injectors. The oil pressure is about 0.1-0.8at. For greasing, mineral oils are use with the viscosity of 3-60 degrees E50^C.With how much the peripheral speed is smaller, the contact pressure and the roughness are higher, and more viscous oils are used.On speed reducers with more gears, the oil is chosed with a viscosity corresponding to the steps that transmit the biggest torque. For the oil bath volume are considered 0.25-0.5l of oil over a horsepower. The period of oil change is about 1000-5000 hours of functioning (for the case when the gearing mechanism is sealed and the oil is filtrate every 2500 hours). For filtering can be used magnetic filters. When the speed reducer is new, the oil must be changed after 200-300hours.

Oiling the bearings:

The choose of lubricants for tapered roller bearings and establishing the grease intervals, is done considering the dimension, number of revolutions, load and work temperature of the bearing.Generally, the liquid lubricants have more advantages then the consistent ones: higher physical-chemical stability, can be used at high speeds and temperatures, and also at very low temperatures, easier evacuation of heat produced in the bearing, smaller resistance sported by the rolling bodies.Disadvantages: difficult bearing sealing, loses through leakages in time, etc.Grease lubrication is more advantageous because leads to: simpler bearings construction, easy to seal, with a lower cost, better protection of the rolling part to external impurities, lower lubricant looses.

10. CHOOSING THE MATERIALS AND MANUFACTURING SYSTEM

Materials used for speed reducer construction.

Materials used for gears:

SteelIt is used great steel: steel with carbon0.4-0.6 %C and steel with 0.35-0.45%C low alloyed with Mn, Cr, Cr-Mo, Cr-Ni etc. Steel non alloyed with Cr, Cr=Mo, Cr-Ni, with cyaniding

Cast ironsCast irons are used at gearing which has a easy working, change wheels which don;’ t functioning every time. When it is asking a silent condition may be used normal iron ash.

Used material for axels execution:

Generally the axel which don’ t have a heat treatment are made by normally steel carbon: OL 40,OL 50, OL 60, Stas 500-78.For axel which a big lifting power we can use carbon steel of quality: OLC 35, OLC 45, OLC 60, according to STAS 880-66.In case of axel which have a strong load and are required small dimension are used steel alloyed with crom, Cr-Ni or Cr-Mn.

Marerials used for producing the body.The body because of the stiffness are made by cast irons or by casting steel. Most of the body are made by cast iron with average resistance Fc 200, Fc 250.

Technical safety regulations

At the place where we use a speed reducer we must know some safety regulation The speed reducer must be bolting with screws in bench. We don’t work with speed reducers which don’t have all the components (pieces of

body, casings cover). We don’t change the oil in time of functioning. We don t check the oil level in time of functioning. Damage parts will be replaced with required parts.