6. Analysis of shafts

Let us design the shafts construction.

6.1 Determine the minimum diameter of speed reducer shafts

Input

, assume d=28 mm

d_motor- d_min =38-28≤10 mm,

_whered_motor is the diameter of the electrical motor shaft.

Output:

, assume d=42 mm

6.2. Design the construction of speed reducer shafts.

Fig.6.1. Input shaft

Let us assumed_min=d₁ = 28 mm (according to the standard series);

d₂= d₁ + 2∙t₁= 28 + 2∙ 2=32mm;

d₃= d₂ + 2∙t₂= 32 + 2∙ 1.5= 35 mm;

d₄ = d₃ + 2∙t₁= 35 + 2∙ 5= 40 mm;

Fig.6.2. Output shaft

For our case we should design the output shaft where a straight spur gear is located.

Let us assumed_min=d₁ = 42 mm (according to the standard series);

d₂= d₁ + 2∙t₁= 42 + 2∙ 2.5=47→48 mm;

d₃= d₂ + 2∙t₂= 55 + 2∙ 2.5= 50 mm;

d₄ = d₃ + 2∙t₁= 60 + 2∙ 5= 55 mm;

d₅ = d₄ + 2∙t₁= 70 + 2∙5= 65 mm.

6.3. Determine sizes of elements that are mounted on the shaft.

6.3.1. Pinion.

Face width of the pinion b^p= b^g+ 5=50+5=55 mm.

6.3.2. Spur and bevel gears

- thickness of the rim δ = 3·m=3·2=6 mm;

• thickness of the web C = 0.2·b^g=0.2·50=10 mm;

• diameter of the hub d_hub=1.5·d_shaft=1. 5·55=82.5 mm;

• length of the hub l_hub=1.2·d_shaft=1.2·55=66 mm;

• diameter of the hole ;

• diameter of the hole center line ;

- fillet radii R ≥ 6 mm and angle γ ≥ 7º.

6.3.4. Bearings.

Single - Row Radial Ball Bearings (GOST 8338-75).

Lightweight series

Type designation	d	D	B	r	Basic load rating Cr, kN	Static load rating C0, kN	Shaft
207	35	72	17	2	25.5	13.7	Input
210	50	90	20	2	35.1	19.8	Output

6.3.5. Lip seal.

Standard lip seals (gost 8752-79)

Input: 32x52x10

Output 48x70x10

6.3.6. Sprocket

- diameter of the hub d_hub=1.5·d_shaft=1.5·42=63 mm

- length of the hub l_hub=1.2·d_shaft=1.2·42=52.4 mm

- thickness of the web C = 0.93·B_bush=0.93·19.05=17.71 mm

6.3.8. Coupling.

Standard couplings with rubber bushed studs (GOST 21424 – 93)

Torque T, N∙m	d	D, not more	L			l		D1		l1	l2		d2		d3		B		B1	d1	Number of studs
			Modification
			1		1
125	28	120	125		60				90	16		20		40		20		4	28	M10	6