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GB/T 32321-2015 English PDF (GBT32321-2015)

GB/T 32321-2015 English PDF (GBT32321-2015)

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GB/T 32321-2015: Rolling bearings -- Sealed deep groove ball bearings -- Performance test rule of dustproofing, grease leakage and temperature rise

This Standard specifies performance test rule of dustproofing, grease leakage and temperature rise for general-purpose sealed deep groove ball bearings, of which the dimensions meet the diameter series 0, 2, 3 in GB/T 276, nominal inner diameter. 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.
GB/T 32321-2015
NATIONAL STANDARD OF THE
PEOPLE 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
???????????? ?????????????????????
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 __________

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