GB/T 32321-2015 PDF English
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Rolling bearings -- Sealed deep groove ball bearings -- Performance test rule of dustproofing, grease leakage and temperature rise
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GB/T 32321-2015: PDF in English (GBT 32321-2015) GB/T 32321-2015
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 21.100.20
J 11
Rolling bearings - Sealed deep groove ball bearings -
Performance test rule of dustproofing, grease leakage
and temperature rise
滚动轴承 密封深沟球轴承
ISSUED ON: DECEMBER 31, 2015
IMPLEMENTED ON: APRIL 01, 2016
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Terms and definitions ... 4
4 Symbols ... 5
5 Test preparations ... 6
6 Test conditions ... 7
7 Test processes ... 8
8 Test results ... 9
Foreword
This Standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This Standard was proposed by China Machinery Industry Federation.
This Standard shall be under the jurisdiction of National Technical Committee
on Rolling Bearings of Standardization Administration of China (SAC/TC 98).
The drafting organizations of this Standard: Luoyang Bearing Research
Institute Co., Ltd.
Main drafters of this Standard: Zhang Wei, Zheng Zhigong, Zhang Zhenchao.
Rolling bearings - Sealed deep groove ball bearings -
Performance test rule of dustproofing, grease leakage
and temperature rise
1 Scope
This Standard specifies performance test rule of dustproofing, grease leakage
and temperature rise for general-purpose sealed deep groove ball bearings
(both sides are with sealing rings or both sides are with dust covers), of which
the dimensions meet the diameter series 0, 2, 3 in GB/T 276, nominal inner
diameter d≤60 mm (hereinafter referred to as sealed ball bearings). The
bearings of other types, sizes and size ranges shall refer to this Standard to
use.
This Standard is applicable to dustproofing, grease leakage and temperature
rise tests for sealed ball bearings on test devices.
2 Normative references
The following referenced documents are indispensable for the application of
this document. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any
amendments) applies.
GB/T 276, Rolling bearings - Deep groove ball bearings - Boundary
dimensions
GB/T 2479, Conventional abrasive - White fused alumina
GB/T 2828.1, Sampling procedures for inspection by attributes - Part 1:
Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot
inspection
SH/T 0336, Grease impurities assay (microscopy)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 dustproofing performance of sealed ball bearings
the ability of sealed ball bearings to prevent external dust from entering the
interior of the bearing chamber during bearing operation
3.2 dustproofing performance test
the test that when the sealed ball bearing is placed in a specific dust
environment, when it is running under the specified test conditions, determine
its dustproofing performance according to the invasion of external dust into the
interior of bearing chamber
3.3 grease leakage performance of sealed ball bearings
the performance of sealed ball bearings to prevent the grease in the bearing
chamber from leaking to the outside of the bearing during bearing operation
3.4 grease leakage performance test
the test that when sealed ball bearing is running under the specified test
conditions, determine its grease leakage resistance performance according to
the grease leakage in the bearing chamber
3.5 temperature rise performance of sealed ball bearings
the degree of the maximum TEMPERATURE of outer surface of outer ring of
sealed ball bearings THAT IS higher than ambient temperature during bearing
operation
3.6 temperature rise performance test
the test that when sealed ball bearing is running under the specified test
conditions, determine its temperature rise performance according to the
difference BETWEEN the actual measured temperature of outer surface of
outer ring AND ambient temperature
4 Symbols
The symbols given in GB/T 2828.1 as well as the followings apply to this
document.
N: Sample size
n0: Limit speed of contact sealed ball bearings, r/min
V: Effective space volume of dust medium box of dustproofing performance test,
mL
5 Test preparations
5.1 Bearing sample
5.1.1 Randomly extract sample from the finished sealed ball bearings of same
model, same batch that are inspected as accepted.
5.1.2 Extract 12 sets of samples for each test. The test sample size N=8. The
rest 4 sets are for analysis and use.
5.1.3 At the end face of the bearing sample, write item number and serial
number separately and set by set.
5.1.4 Before each test, wipe the surface of bearing sample clean. There shall
be no oil stains and dusts.
5.2 Dust medium
5.2.1 The dust medium used for dustproofing performance test is white
corundum that the granularity meets the provisions of GB/T 2479, that is
marked as F240 (micro-powder).
5.2.2 Bake the dust medium in a drying oven at 110°C ± 10°C for 1 h. Place in
a dryer to cool.
5.2.3 Use a clean measuring cup to measure the cooled dust medium.
5.3 Mass weighing
5.3.1 The balance used for grease leakage performance test shall be regularly
verified as qualified. Its weighing range and accuracy shall meet the test
requirements.
5.3.2 Weigh the pre-test bearing sample mass before test for grease leakage
performance.
5.4 Temperature measuring apparatus
The temperature measuring apparatus for temperature rise performance test
shall be regularly verified as qualified. Its temperature measuring range and
accuracy shall meet the test requirements.
5.5 Test body assembly
5.5.1 Test spindle diameter tolerance that fits inner diameter of bearing sample
shall select g5. Diameter tolerance of bearing housing hole that fits outer
diameter of bearing sample shall select H6.
5.5.2 Each parts of test body shall be washed clean. The assembled parts shall
meet the technical requirements of assembly pattern.
5.5.3 Bearing sample shall be mounted correctly. It shall not tap or touch the
gasket ring or dust cover so as to prevent deformation.
5.5.4 After bearing sample is mounted, it shall rotate flexibly, without being
blocked.
6 Test conditions
6.1 Test device is the sealed bearing testing machine that passes regular
verification and is verified as qualified.
6.2 Test conditions for bearing sample’s dustproofing, grease leakage,
temperature rise performance are selected according to Table 1, Table 2 and
Table 3, respectively. Test speed error shall be ≤2%. Test load error shall be
≤2%.
6.3 Test speeds of the bearing samples of other types, sizes series and size
ranges shall be selected by referring to Table 1, Table 2 and Table 3. The loads
for grease leakage, temperature rise performance tests shall be selected
according to 1%~2% of bearing’s basic rated dynamic load.
6.4 Effective space volume of dust medium box for dustproofing performance
test shall not be less than 500 mL. The dust-filling amount shall be added
according to Table 1. It shall make both sides of bearing sample dusted evenly.
6.5 Rotating direction of dust medium box for dustproofing performance test
shall be opposite to bearing sample’s rotating direction.
Table 1 -- Dustproofing performance test conditions
Nominal inner
diameter of bearing
mm Test
speed
r/min
Dust medium box
Ambient
temperature
°C
Test
time
Dust-filling amount
mL
Rotating
speed
r/min > ≤
Contact,
non-
contact
sealed ball
bearings
Sealed
ball
bearings
with dust
cover
- 10
0.3n0
0.4%V 0.2%V
50 10~30 6 10 20 0.4%V 0.2%V 20 30 0.5%V 0.25%V
30 40 0.6%V 0.3%V
40 50 0.6%V 0.3%V
50 60 0.7%V 0.35%V
NOTE: The limit speeds of non-contact sealed ball bearings and sealed ball bearings with dust cover
shall be selected according to the limit speed for contact sealed ball bearings of same dimensions n0.
Table 2 – Grease leakage performance test conditions
Nominal inner
diameter of
bearing
mm
Test
speed
r/min
Test load
N Ambient
temperature
°C
Test
time
h Diameter series 0 Diameter series 2, 3
> ≤ Radial Axial Radial Axial
- 10
0.3n0
69 0 98 0
10~30 6
10 20 78 0 196 0
20 30 147 0 294 0
30 40 245 0 392 0
40 50 314 0 490 0
50 60 431 0 588 0
NOTE: Same as the note in Table 1.
Table 3 – Temperature rise performance test conditions
Nominal inner
diameter of
bearing
mm
Test
speed
r/min
Test load
N Ambient
temperat
ure
°C
Test
time
h Diameter series 0 Diameter series 2, 3
> ≤ Radial Axial Radial Axial
- 10
0.75n0
69 0 98 0
10~30 6
10 20 78 0 196 0
20 30 147 0 294 0
30 40 245 0 392 0
40 50 314 0 490 0
50 60 431 0 588 0
NOTE: Same with the note in Table 1.
7 Test processes
7.1 During the dustproofing, grease leakage and temperature rise performance
tests, observe the operation of bearing sample at any time. When there are
abnormal vibration, noise and other anomalies, it shall turn off the machine
timely.
7.2 Whenever bearing sample fails due to malfunction of test device, instrument
or improper operation, it shall take spare samples to carry out the tests in turn
again.
7.3 For temperature rise performance test, in general, it shall continuously
record the bearing sample’s temperature and ambient temperature.
7.4 For grease leakage, temperature rise performance tests, it shall turn the
machine on and off when there are loads.
8 Test results
8.1 Dustproofing performance test
After the dustproofing performance test, wipe the externally-attached dust
medium and leaked grease clean. Use special tool to dismantle the gasket ring
or dust cover of bearing sample. According to the provisions of SH/T 0336,
respectively and evenly take grease sample from both ends to check the dust
invasion amount.
The dust amount of grease average unit volume in single set of bearing samples
is calculated according to formula (1):
Where,
X - Dust amount of average unit volume, piece/cm3;
A - Sum of dust amounts in 10 grease samples, piece/cm3;
400 - Coefficient for volume of observed grease sample (0.0025 cm3) being
converted to 1 cm3;
10 - Number of sampling.
NOTE: Before bearing sample test, the average dust amount can be neglected. After the
test of single set of bearing samples, the average dust amount shall be the dust invasion
amount of this set of bearing samples.
8.2 Grease leakage performance test
After grease leakage performance test, wipe off the grease leaked from outside
bearing sample and oil stains. Weigh the post-test bearing sample mass. Use
special tool to dismantle the gasket ring or dust cover. Clean off the grease
inside the bearing sample as well as the grease on the gasket ring or dust cover.
Weigh the net mass of bearing sample after it is dried (including the mass of
gasket ring or dust cover).
The grease leakage rate of single set of bearing samples is calculated
according to formula (2):
Where,
Grease leakage amount of single set of bearing samples = Pre-test bearing
sample mass – Post-test bearing sample mass
Grease filling amount of singe set of bearing samples = Pre-test bearing sample
mass – Net mass of bearing sample
8.3 Temperature rise performance test
The temperature rise of bearing sample is the difference BETWEEN the actual
measured temperature of outer ring’s outer surface of bearing sample AND the
ambient temperature at this moment. The temperature rise of single set of
bearing samples is the maximum value of actual measured temperature rise of
bearing sample within the test time.
8.4 Test determination
8.4.1 Dustproofing, grease leakage, temperature rise performance of bearing
sample shall be determined according to Table 4 set by set, respectively.
Table 4 -- Determination of dustproofing, grease leakage, temperature
rise performance tests
Dust invasion amount of
dustproofing performance
test
Piece/cm3
Grease leakage rate of grease
leakage performance test
Temperature rise of temperature
rise performance test
°C
Non-contact
sealed ball
bearings,
sealed ball
bearings
with dust
cover
Contact
sealed ball
bearings
Non-contact
sealed ball
bearings,
sealed ball
bearings with
dust cover
Contact sealed
ball bearings
Non-contact
sealed ball
bearings,
sealed ball
bearings with
dust cover
Contact sealed
ball bearings
80000 16000 10 5 45 55
8.4.2 During the test of bearing sample, if gasket ring or dust cover falls off, if
Grease leakage rate of
single set of bearing
samples
Amount of grease leakage
of single set of bearing
samples
Amount of grease filling of
single set of bearing
samples
grease leaks at outer ring sealed groove, if gasket ring or dust cover rotates
relatively to outer ring, this item of performance of this set of bearing samples
shall be determined as rejected.
8.4.3 The determination of dustproofing, grease leakage and temperature rise
performance tests of sealed ball bearings shall, according to GB/T 2828.1,
adopt the one-time sampling scheme of normal inspection, of which the sample
size N=8, the acceptance quality limit AQL is 6.5, the number of acceptance for
each test Ac is 1, and the number of rejection Re is 2.
__________ END __________
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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