Table 11.1

Values of X, Y and e for some types of bearings

Type of bearing	a°	F_a/C _o	F_a/ (VF_r)£ e	F_a /(VF_r)> e	e
X	Y	X	Y
Single Row radial Ball Bearing		0.014			0.56	2.30	0.19
0.028	1.99	0.22
0.056	1.71	0.26
0.084	1.55	0.28
0.11	1.45	1.30
0.17	1.31	0.34
0.28	1.15	0.38
0.42	1.04	0.42
0.56	1.00	0.44
Single Row Angular Contact Ball Bearing		0.014			0.45	1.81	0.30
0.029	1.62	0.34
0.057	1.46	0.37
0.086	1.34	0.41
0.11	1.22	0.45
0.17	1.13	0.48
0.29	1.14	0.52
0.43	1.01	0.54
0.57	1.00	0.54
	–			0.41	0.87	0.68
	–			0.37	0.66	0.95
Single row Tapered Roller Bearing		–			0.4	0.4ctga	1.5ctga

11.2.3. Determine total axial forces F_a ₁ and F_a ₂. For that we should find the sum F_a + S ₁and compare with force S _2.There are 3 possible cases:

– if F_a + S ₁> S ₂ F_a ₁= S ₁ and F_a ₂= F_a + S ₁;

– if F_a + S ₁= S ₂ F_a ₁= S ₁ and F_a ₂= S ₂;

– if F_a + S ₁< S ₂ F_a ₁= S ₂– F_a and F_a ₂= S ₂.

In our case F_a + S ₁ = 346.7 +2247.5 = 2594.2 N < S ₂ = 2961.1 N, therefore F_a ₁= 2961.1 – 346.7 = 2614.4 N and F_a ₂= 2961.1 N.

11.3. Determine factor V that takes into account what ring of the bearing is movable.

– for bearings with movable inner ring V = 1;

– for bearings with movable outer ring V = 1.2.

In general purpose speed reducers bearings with movable inner ring are used only.

11.4. Determine safety factor K_s that takes into account the load nature. It may be ranged from 1 to 2.5 depending upon the type of designing machine. For general purpose speed reducers the safety factor is assumed as 1.3.