The Problem Of Preventing Bearing Vibration From Simple Bearing Design
The Problem Of Preventing Bearing Vibration From Simple Bearing Design
2022年1月6日
Model And Dimension Specification Of Self-Aligning Roller Bearing
Model And Dimension Specification Of Self-Aligning Roller Bearing
2022年1月6日

Selection Principle Of Bearing Clearance

Selection Principle

Selection principle of clearance:

1. Large clearance group should be used when tight fit is adopted, the temperature difference between inner and outer rings is large, the friction Selection Principle torque needs to be reduced, the deep groove ball bearing bears large axial load or the centering performance needs to be improved.

2. When the rotation accuracy is required to be high or the axial displacement needs to be strictly Selection Principle limited, the small clearance group should be used.

Factors related to clearance:

1. Fit between bearing inner race and shaft.

2. Fit between bearing outer ring and housing hole.

3. Temperature effect.

Note: the reduction of radial clearance is related to the actual effective Selection Principle interference of mating parts, the size of mating shaft diameter and the wall thickness of shell hole.

1. The actual effective interference (inner ring) shall be: △ dy = 2 / 3 △ D – g * △ D is

Nominal interference, g * is the flattening size of interference fit.

2. The actual effective interference (outer ring) shall be: △ dy = 2 / 3 △ D – g * △ D is

Nominal interference, g * is the Selection Principle flattening size of interference fit.

3. The heat generated will cause the temperature inside the bearing to rise, which in turn will cause the expansion of the shaft, bearing pedestal and bearing parts. The clearance can be increased or decreased depending on the material of the shaft and bearing pedestal and the temperature between the bearing and the bearing support components.

Calculation formula of clearance:

(1) : impact of coordination

1. Bearing inner ring and steel solid shaft: △ J = △ dy * D / h

2. Bearing inner ring and steel hollow shaft: △ J = △ dy * f (d)

F(d) = d/h * [(d/d1)2 -1]/[(d/d1)2 – (d/h)2]

3. Bearing outer ring and steel solid shell: △ a = △ dy * H / D

4. Bearing outer ring and steel thin wall shell: △ a = △ dy * f (d)

F(D) = H/D * [(F/D)2 – 1]/[(F/D)2 – (H/D)2]

5. Bearing outer ring and gray cast iron housing: △ a = △ dy * [f (d) – 0.15]

6. Bearing outer ring and light metal housing: △ a = △ dy * [f (d) – 0.25]

Note:

△ J — expansion of inner ring raceway retaining diameter (UM).

△ dy – effective interference of Journal (UM).

D — Nominal Dimension of bearing inner diameter (mm).

H — diameter of inner ring raceway flange (mm).

B — bearing width (mm).

D1 — inner diameter of hollow shaft (mm).

△ a — shrinkage of outer ring raceway flange diameter (mm).

△ dy — actual effective interference of shell hole diameter (UM).

H — diameter of outer ring raceway flange (mm).

D — nominal diameter of bearing outer ring and housing hole (mm).

F — outer diameter of bearing housing (mm).

(2) : effect of temperature

△T = Г b * [De * ( T0–Ta )–di * ( Ti–Ta)]

among Г B is the linear expansion Selection Principle coefficient, and the bearing steel is 11.7 * 10-6 mm / mm / 0C

De is the raceway diameter of the bearing outer ring and Di is the Selection Principle raceway diameter of the bearing inner ring.

TA is the ambient temperature.

T0 is the temperature of bearing outer ring and Ti is the temperature of bearing inner ring.

4、 Relationship between axial Selection Principle clearance and radial clearance:

Ua = [4(fe + fi–1) * Dw * Ur–Ur2 ] 1/2

Because the radial clearance ur is very small, UR2 is very small, which is ignored.

Therefore, UA = 2 * [(Fe + fi – 1) * DW * ur] 1 / 2

Where Fe is the curvature coefficient of outer ring groove, FI is the Selection Principle curvature coefficient of inner ring groove, and DW is the diameter of steel ball

Query of bearing clearance standard

(mm)

Bearing inner diameter greater than D to twenty-four twenty-four thirty thirty forty forty fifty fifty sixty-five sixty-five eighty eighty one hundred one Selection Principle hundred one hundred and twenty one hundred and twenty one hundred and

forty one hundred and forty one hundred and sixty one hundred and sixty one hundred and eighty one hundred and eighty two hundred two hundred two hundred and twenty-five two hundred and twenty-five two hundred and fifty

Inner diameter clearance of cylinder( μ m)

Group C2 min max ten twenty fifteen twenty-five fifteen thirty twenty thirty-five twenty forty thirty fifty thirty-five sixty forty seventy-five fifty ninety-five sixty one hundred and ten sixty-five one hundred and twenty seventy one hundred and thirty eighty one hundred and forty ninety one hundred and fifty

C0 group min max twenty thirty-five twenty-five forty thirty forty-five thirty-five fifty-five forty sixty-five fifty eighty sixty one hundred seventy-five one hundred and twenty ninety-five one hundred and forty-five one hundred and ten one hundred and seventy one hundred and twenty one hundred and eighty one hundred and thirty two hundred one hundred and forty two hundred and twenty one hundred and fifty two hundred and forty

C3 group min max thirty-five forty-five forty fifty-five forty-five sixty fifty-five seventy-five sixty-five ninety eighty one hundred and ten one hundred one hundred and thirty-five one hundred and twenty one hundred and sixty one hundred and forty-five one hundred

and ninety one hundred and seventy two hundred and twenty one hundred and eighty two hundred and forty two hundred two hundred and sixty two hundred and twenty two hundred and ninety two hundred and forty three hundred and twenty

C4 group min max forty-five sixty fifty-five seventy-five sixty eighty seventy-five one hundred ninety one hundred and twenty one hundred and ten one hundred and forty-five one hundred and thirty-five one hundred and eighty one hundred and sixty two hundred and

ten one hundred and ninety two hundred and forty two hundred and twenty two hundred and eighty two hundred and forty three hundred and ten two hundred and sixty three hundred and forty two hundred and ninety three hundred and eighty three hundred and twenty four hundred and twenty

Selection Principle Of Bearing Clearance

C5 group min max sixty seventy-five seventy-five ninety-five eighty one hundred and five one hundred one hundred and twenty-five one hundred and twenty one hundred and fifty one hundred and forty-five one hundred and

eighty one hundred and eighty two hundred and twenty-five two hundred and ten two hundred and sixty two hundred and forty three hundred two hundred and eighty three hundred and fifty three hundred and ten three hundred and

ninety two hundred and forty four hundred and thirty three hundred and eighty four hundred and seventy four hundred and twenty five hundred and twenty

Clearance of conical inner hole( μ m)

Group C2 min max fifteen twenty-five twenty thirty twenty-five thirty-five thirty forty-five forty fifty-five fifty seventy fifty-five eighty sixty-five one hundred eighty one hundred and twenty ninety one hundred and thirty one hundred one hundred and forty one hundred and ten one hundred and sixty one hundred and twenty one hundred and eighty one hundred and forty two hundred

C0 group min max twenty-five thirty-five thirty forty thirty-five fifty forty-five sixty fifty-five seventy-five seventy ninety-five eighty one hundred and ten one hundred one hundred and thirty-five one hundred and twenty one hundred and sixty one hundred and

thirty one hundred and eighty one hundred and forty two hundred one hundred and sixty two hundred and twenty one hundred and eighty two hundred and fifty two hundred two hundred and seventy

C3 group min max thirty-five forty-five forty fifty-five fifty sixty-five sixty eighty seventy-five ninety-five ninety-five one hundred and twenty one hundred and ten one hundred and forty one hundred and thirty-five one hundred and seventy one hundred and sixty two hundred one hundred and

eighty two hundred and thirty two hundred two hundred and sixty two hundred and twenty two hundred and ninety two hundred and fifty three hundred and twenty two hundred and seventy three hundred and fifty

C4 group min max forty-five sixty fifty-five seventy-five sixty-five eighty-five eighty one hundred ninety-five one hundred and twenty one hundred and twenty one hundred and fifty one hundred and forty one hundred and eighty one hundred and seventy two hundred and twenty two hundred two hundred and

sixty two hundred and thirty three hundred two hundred and sixty three hundred and forty two hundred and ninety three hundred and seventy three hundred and twenty four hundred and ten three hundred and fifty four hundred and fifty

C5 group min max sixty seventy-five seventy-five ninety-five eighty-five one hundred and five one hundred one hundred and thirty one hundred and twenty one hundred and sixty one hundred and fifty two hundred one hundred and eighty two hundred and

thirty two hundred and twenty two hundred and eighty two hundred and sixty three hundred and thirty three hundred three hundred and eighty three hundred and forty four hundred and thirty three hundred and seventy four hundred and seventy four hundred and ten five hundred and twenty four hundred and fifty five hundred and seventy

C3 – radial clearance of radial bearing, larger than the standard clearance;

MC3 – radial clearance standard clearance of small and micro ball bearings.

Details are as follows:

C1 – radial clearance of radial bearing, smaller than C2 clearance.

C2 – radial clearance of radial bearing, smaller than the standard clearance.

CN (omitted) – Radial Standard clearance of radial bearing.

C3 – radial clearance of radial bearing, larger than the standard clearance.

C4 – radial clearance of radial bearing, larger than C3 clearance.

C5 – radial clearance of radial bearing, larger than C4 clearance.

CC1 – radial clearance of cylindrical roller bearing (non interchangeable), smaller than CC2 clearance.

CC2 – radial clearance of cylindrical roller bearing (non interchangeable), smaller than the standard clearance.

CC — Radial Standard clearance of cylindrical roller bearing (non interchangeable).

CC3 – radial clearance of cylindrical roller bearing (non interchangeable), which is larger than the standard clearance.

CC4 – radial clearance of cylindrical roller bearing (non interchangeable), larger than CC3 clearance.

CC5 – radial clearance of cylindrical roller bearing (non interchangeable), larger than CC4 clearance.

MC1 – radial clearance of small and micro ball bearing, smaller than that of MC2.

MC2 – radial clearance of small and micro ball bearing, smaller than that of MC3.

MC3 – radial clearance and standard clearance of small and micro ball bearings.

MC4 – radial clearance of small and micro ball bearing, larger than MC3 clearance.

MC5 – radial clearance of small and micro ball bearing, larger than MC4 clearance.

MC6 – radial clearance of small and micro ball bearing, larger than that of MC5.

Cm — radial clearance of deep groove ball bearing and cylindrical roller bearing for motor.

CT – radial clearance of cylindrical roller bearing for motor

How to measure the clearance of rolling bearing

Proper installation clearance is helpful to the normal operation of rolling bearing. If the clearance is too small, the temperature of the rolling bearing rises and cannot work normally, so that the rolling element is stuck; Excessive clearance, equipment vibration and rolling bearing noise.

The inspection method of radial clearance is as follows:

Sensory method

 

1. Rotate the bearing by hand, and the bearing shall be stable and flexible without jamming.

 

2. Shake the outer ring of the bearing by hand. Even if the radial clearance is only 0.01mm, the axial movement of a point on the bearing is also 0.10 ~ 0.15mm. This method is dedicated to single row radial ball bearings.

 

Measurement method

 

1. Check with a feeler gauge to confirm the heavy load part of the rolling bearing. Insert a feeler gauge between the rolling element at 180 ° and the outer (inner) ring. The thickness of the feeler gauge with appropriate tightness is the radial clearance of the bearing. This method is widely used in self-aligning bearings and cylindrical roller bearings.

 

2. Check with a dial indicator. First set the dial indicator to zero, and then jack up the outer ring of the rolling bearing. The reading of the dial indicator is the radial clearance of the bearing.

 

The inspection method of axial clearance is as follows:

 

1. Sensory method

 

Check the axial clearance of rolling bearing with finger. This method is applied to the occasion where the shaft end is exposed. When the shaft end is closed or cannot be checked by fingers for other reasons, check whether the shaft rotates flexibly.

 

2. Measurement method

 

(1) Check with a feeler gauge. The operation method is the same as that of checking the radial clearance with a feeler gauge, but the axial clearance shall be

 

c= λ/ (2sin β)

 

Where C — axial clearance, mm;

 

λ—— Feeler gauge thickness, mm;

 

β—— Bearing cone angle, (°).

 

(2) Check with a dial indicator. When the shaft is moved with a crowbar so that the shaft is at two extreme positions, the difference between the readings of the dial indicator is the axial clearance of the bearing. However, the force applied to the crowbar shall not be too large, otherwise the shell will undergo elastic deformation. Even if the deformation is very small, it will affect the accuracy of the measured axial clearance.