Bearing tolerance measurement methods

This section outlines measuring methods for dimensional tolerances and running accuracy.

Dimensional accuracy

Bore diameter(d)Cylindrical bore bearings

Obtain the maximum value (d_{sp max}) and the minimum value (d_{sp min}) of the bore diameter (d_s) acquired in a single radial plane. Obtain the single plane mean bore diameter (d_mp) as the arithmetic mean value of the maximum value (d_{sp max}) and minimum values (d_{sp min}).

d_mp=(d_{sp max}+d_{sp min}) / 2
Single plane mean bore diameter deviation
Δ_dmp = d_mp - d
Bore diameter variation in a single plane
V_dsp = d_{sp max} - d_{sp min}
Mean bore diameter variation
V_dmp = d_{mp max} - d_{mp min}
Deviation of a single bore diameter
Δ_ds = d_s - d

Bore diameter(d) Tapered bore bearings

d_s = (d_bs * h_a - d_as * h_b) / (h_a - h_b)
d_1s = [d_as(B - h_b) - d_bs(B - h_a)] / (h_a - h_b)
Single plane mean bore diameter deviation at the theoretical small end
Δ_dmp = d_mp - d
Deviation on taper
(Δ_d1mp - Δ_dmp) = (d_1mp - d₁) - (d_mp - d)
Bore diameter variation in a single plane
V_dsp = d_{sp max} - d_{sp min}

Outside diameter(D)

Obtain the single plane mean outside diameter (D_mp) as the arithmetical mean value of the maximum value (D_{sp max}) and the minimum value (D_{sp min}) of the outside diameters (D_s) acquired in a single radial plane.

D_mp = (D_{sp max} + D_{sp min}) / 2
Single plane mean outside diameter deviation
Δ_Dmp = D_mp - D
Outside diameter variation in a single plane
V_Dsp = D_{sp max} - D_{sp min}
Mean outside diameter variation
V_Dmp = D_{mp max} - D_{mp min}
Deviation of a single outside diameter
Δ_Ds = D_s - D

Roller set bore diameter(F_w)

Deviation of the roller set bore diameter
Δ_Fw = (d_G + δ_1m) - F_w
Deviation of the minimum diameter of the roller set bore diameter Δ_Fwmin = (d_G + δ_1min) - F_w

(d_G)outside diameter of the master gauge
(δ_1m)arithmetical mean value of the amount of movement of the outer ring
(δ_1min)minimum value of the amount of movement of the outer ring

Roller set outside diameter(E_w)

Deviation of the roller set outside diameter
Δ_Ew = (D_G + δ_2m) - E_w

(D_G)bore diameter of the master gauge
(δ_2m)arithmetical mean value of the amount of movement of the master gauge

Inner ring width(B)

Deviation of a single inner ring width
Δ_Bs = B_s - B
Inner ring width variation
V_Bs = B_smax - B_smin

Outer ring width(C)

Deviation of a single outer ring width
Δ_Cs = C_s - Cs
Outer ring width variation
V_Cs = C_smax - C_smin

Assembled bearing width of tapered roller bearing(T)

Deviation of the actual bearing width
Δ_Ts = T_s - T

Nominal effective width of tapered roller bearing(T₁,T₂)

Deviation of the actual effective width of inner sub-unit
Δ_T1s = T_1s - T₁

Deviation of the actual effective width of outer ring
Δ_T2s = T_2s - T₂

Nominal height of thrust ball bearing with flat back face(T,T₁)

Deviation of the actual bearing height
Δ_Ts = T_s - T(single direction)
Δ_T1s = T_1s - T₁ (double direction)

Running accuracy

Radial runout of assembled bearing inner ring(K_ia)

The radial runout of the inner ring (K_ia) shall be obtained as the difference between the maximum value and the minimum value of the readings of the measuring instrument, when the inner ring has been rotated through one rotation.

[Note]
The measurement of the radial runout of the inner ring of cylindrical roller bearings, machined ring needle roller bearings, selfaligning ball bearings and spherical roller bearings shall be carried out by fixing the outer ring with ring supports.

Radial runout of assembled bearing outer ring(K_ea)

The measurement of outer ring runout (K_ea) shall be obtained as the difference between the maximum value and the minimum value of the readings of the measuring instrument, when the outer ring has been rotated through one rotation.

[Note]
The measurement of the radial runout of the outer ring of cylindrical roller bearings, machined ring needle roller bearings, self-aligning ball bearings and spherical roller bearings shall be carried out by fixing the inner ring with ring supports.

Axial runout of assembled bearing inner ring(S_ia)

The axial runout of the inner ring (S_ia) shall be obtained as the difference between the maximum value and the minimum value of the readings of the measuring instrument, when the inner ring has been rotated through one rotation.

Axial runout of assembled bearing outer ring(S_ea)

The axial runout of the outer ring (S_ea) shall be obtained as the difference between the maximum value and the minimum value of the readings of the measuring instrument, when the outer ring has been rotated through one rotation.

Perpendicularity of inner ring face with respect to the bore(S_d)

Perpendicularity of inner ring face (S_d) shall be obtained as the difference between the maximum value and the minimum value of the readings of the measuring instrument, when the inner ring has been rotated through one rotation with the tapered arbor.

Perpendicularity of outer ring outside surface with respect to the face(S_D)

Perpendicularity of outer ring outside surface (S_D) shall be obtained as the difference between the maximum value and the minimum value of the readings of the measuring instrument, when the outer ring has been rotated through one rotation along the guide stopper.

Shaft/central race raceway to back face thickness variation of thrust ball bearing with flat back face(S_i)

The measurement of the thickness variation (S_i) of shaft race raceway track shall be obtained as the difference between the maximum value and the minimum value of the readings of the measuring instrument, when the shaft race has been rotated through one rotation along the guide stopper. For the central race, carry out the same measurement for the two raceway grooves to obtain the thickness variation of the raceway track (S_i).

Housing race raceway to back face thickness variation of thrust ball bearing with flat back face(S_e)

The measurement of the thickness variation (S_e) of housing race raceway track shall be obtained as the difference between the maximum value and the minimum value of the readings of the measuring instrument, when the housing race has been rotated through one rotation along the guide stopper.