JB/T 7050-1993 Rolling bearing cleanliness and evaluation method JB/T7050-1993 standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T 7050-1993
Rolling Bearings
Cleanliness and Assessment Methods
Published on September 23, 1993
Ministry of Machinery Industry of the People's Republic of China
Implemented on July 1, 1994
Mechanical Industry Standard of the People's Republic of China
Rolling Bearings
Cleanliness and Assessment Methods
Subject Content and Scope of Application
This standard specifies the cleanliness requirements for finished rolling bearings (bearing outer diameter ≤ 180mm). This standard applies to manufacturers' inspection of the cleanliness of bearings of various tolerance grades. 2 Definition
Bearing cleanliness refers to the control index of the dirt still remaining in the finished bearing after effective cleaning. 3 Technical requirements
JB/T7050-1993
The cleanliness of the finished bearings that have passed the inspection and are oil-sealed is evaluated by the allowable average dirt content per set: For rolling bearings with G, E, and D tolerances, the allowable average dirt content per set should not exceed the provisions of Table 1: The limit for C-class bearings is 0.7 times the value of the same size segment listed in Table 1, and for B-class bearings it is 0.5 times.
Table 1 Allowable average dirt content W of rolling bearings
Bearing nominal
Outer diameter D
Deep groove ball bearings
8, 9, 0
Approved by the Ministry of Machinery Industry on September 23, 1993
Closed deep groove ball bearings
Diameter series
Deep groove with retaining groove
Ball bearings
The maximum allowable value of the average dirt content in each set of bearings 1.2
Double row deep groove
Ball Bearing
mg/set
1994-07-01 implementation
Bearing nominal
Outer diameter D
Bearing nominal
Outer diameter D
Angular contact ball bearing
Self-aligning ball bearing
JB/T7050-1993
Continued Table 1
Double row angular contact ball bearing
Diameter series
One-way thrust ball bearing
Average amount of contaminants in each set of bearings Maximum allowable value of the quantity 2.4
Cylindrical bearing
Double row cylindrical
Lacquer bearing
Tapered bearing
Diameter system
The maximum allowable value of the average amount of dirt in each set of bearings
Double direction thrust ball bearing
mg/set
Double row tapered
Roller auxiliary bearing
Spherical roller bearing
0, 1, 23
mg/set
Bearing nominal
Outer diameter D
Test conditions
Self-aligning ball bearing
JB/T7050-1993
Table 2
Cylindrical roller bearings
Double-row cylindrical
Roller bearings
Tapered roller bearings
The maximum allowable value of the average dirt content in each set of bearings is 12.4
For general requirements and determination of dust reduction in the workplace, see Appendix A (supplement). 5 Measurement method
Instruments, materials and tools
a. Small ultrasonic cleaning machine, 250W:
b. Vacuum pump, 30L/min;
c. Constant temperature drying oven:
d. Microporous filter, M-50;
e. Suction filter bottle, capacity greater than 1L;
f. Stainless steel cup or glass beaker, diameter range 80-200cm;
h. Special clamp:
i. Analytical balance, sensitivity 0.1mg;
j. Special filter membrane, BRC- M1.2:
k. Flat weighing bottle, diameter greater than 60mm; 1. Dryer;
m. Washing bottle:
Double-row tapered
Roller bearing
Spherical roller bearing
0, 1, 2
mg/set
n.120# solvent gasoline (technical indicators meet GB1922-80 "Solvent Oil" and filtered through 0.45um filter membrane); 0. Special co-solvent, BRC-F1;
P. Special co-solvent, BRC-F2:
qCentrifuge, BRC-800.
5.2 Test
JB/T7050-1993
5.2.1 Use tweezers to take 2 BRC-M1.2 special filter membranes (1 for control) and put them into a half-open weighing bottle, and dry them in a constant temperature drying oven at 90±5℃ for 30 minutes.
5.2.2 Use tweezers to take out the weighing bottle from the constant temperature drying oven and put it into the dryer to cool for 30 minutes, then use tweezers to take out the filter membrane, weigh it respectively and record the data, record it as P test 1, P control 1. 5.2.3 Select the number of sample bearings according to the size and batch of bearings, but the sample bearings shall not be less than 5 sets. 5.2.4 According to the size and number of sample bearings, select a clean container of appropriate size, put all the sample bearings and add an appropriate amount of 120# solvent gasoline, degrease and degrease the sample bearings, and place them for 2 hours. 5.2.5 According to the size of the sample bearing, select two clean beakers of appropriate size and add equal amounts of 120# solvent gasoline to each beaker. The amount of solvent should not be less than 200mL. The depth of the solvent in the beaker should be twice the width of a set of sample bearings. 5.2.6 Place the two beakers with solvent into the cleaning tank of the ultrasonic cleaning machine at the same time (inject more than one-third of the tank volume of water into the tank), and the distance between the bottom of the cup and the bottom of the tank should be controlled at 10~25mm. 5.2.7 Use special clamps to take a set of sample bearings and place them flat in two beakers for cleaning. The cleaning time is 1min each. 5.2.8 Use special clamps to take the sample bearing out of the second beaker, and use a washing bottle filled with 120# solvent gasoline to spray the bearing sample 1-2 times, and collect the washing liquid into another clean beaker. 5.2.9 Repeat steps 5.2.7 and 5.2.8 until a set of sample bearings are cleaned, and then take the beaker out of the cleaning tank. 5.2.10 Take out the two weighed special filter membranes from the weighing bottle with a plating knife, put them into clean 120 solvent gasoline, and place them on the mesh plate of the microporous filter after fully wetting. The upper membrane is the test filter membrane, and the lower membrane is the control filter membrane. Connect the suction filter bottle and the vacuum pump system. 5.2.11 Put the container of 120# solvent gasoline containing anti-rust oil and a small amount of dirt obtained by degreasing the sample bearing according to the steps of Article 5.2.4 into the ultrasonic filter cleaning machine, and gradually add BRC-F1 solvent (BRC-F2 is used for grease) under the action of ultrasonic wave, and stir ultrasonically for 5 minutes until all the tangles in the solution are dissolved into a transparent system. 5.2.12 Start the centrifuge to centrifuge the solution treated in step 5.2.11 for 2 minutes, and then start the vacuum pump to vacuum filter the above solution under vacuum decompression conditions, and then use a washing bottle to spray the inner wall and bottom of the container 2~3 times, and the washing liquid is also filtered under reduced pressure. 5.2.13 Place the beaker of 120# solvent gasoline containing a small amount of anti-rust oil and a large amount of dirt obtained by ultrasonic cleaning of a group of sample bearings according to step 5.2.9 into an ultrasonic cleaning machine, gradually add BRC-F1 solvent (BRCF2 is used for grease) under the action of ultrasound, and stir ultrasonically for 5 minutes until all the tangled substances in the solution are dissolved into a transparent system. 5.2.14 Start the centrifuge and centrifuge the solution treated in step 5.2.11 for 2 minutes, then start the vacuum pump to vacuum filter the above liquid under vacuum decompression (the same filter membrane as step 5.2.12), then use a washing bottle to spray the inner wall and bottom of the beaker 2-3 times, and the washing liquid is also filtered under reduced pressure.
5.2.15 Use a washing bottle to spray and wash the inner wall and bottom of the filter 2-3 times, then remove the filter and take out the control filter membrane and the test filter membrane. 5.2.16 Repeat the steps of 5.2.1 and 5.2.2 to dry, cool and weigh the filter membrane after the test, and record the data as Ptest2Pcontrol2°
Calculate the average total contamination content in the bearing according to the following formula WW-(Pta-Ptl)-(Pa2-Pam) 100
Where: W average total contamination content in the bearing, mg/set: 4wwW.bzxz.Net
JB/T7050-1993
Ptest2-weight of the test filter membrane after the test, g:Ptest1-weight of the test filter membrane before the test, g;Pcontrol2-weight of the control filter membrane after the test, g:Pcontrolweight of the control filter membrane before the test, g:N number of sample bearings, sets;
1000 coefficient (1000mg=1g).
5.2.18 If according to 5.2.11 and 5.2.If there are still spherical objects in the solution treated in step 13, W cannot be regarded as correct data and should be indicated in the report.
Inspection rules
The inspection of bearing cleanliness shall be carried out by the quality inspection department of the manufacturer. Sampling
20 sets of ball bearings with an outer diameter less than or equal to 45mm for each specification; 10 sets of ball bearings with an outer diameter greater than 45mm and less than or equal to 80mm for each specification; 5 sets of roller bearings and ball bearings with an outer diameter greater than 80mm for each specification. 5
General requirements
JB/T7050-1993
Appendix A
General requirements and determination of dust reduction in work (supplement)
A1.1 In order to ensure the accuracy of the measurement, a clean special workshop needs to be set up. The workshop should have good dust prevention measures, and the indoor dust reduction shall not exceed 40mg/m2.
A1.2 The test equipment must be cleaned in advance and wiped with a clean white silk cloth. No dirt is allowed on the white silk cloth after wiping. A1.3 The operator should wear clean work clothes, shoes, hats and gloves when working. A2 Determination of dust fall in the workplace
A2.1 Apparatus
a. White plate (3000mmx250mm) or glass plate; b. Microporous filter device, M-50 type.
A2.2 Test
A2.2.1 Place one or more white porcelain plates with oil on the surface in the workshop and record the start time. A2.2.2
After 24 hours, use 120# solvent gasoline to clean all the sediment on the white porcelain plate, filter the washing liquid, dry and weigh, see the corresponding part of the test in Section 3.2.2.2. A2.2.3
A2.2.4 Calculate
W, =Wpy / Sp
-24h dust fall according to formula (A1), mg/m2;
Wp——Total mass falling inside the white porcelain plate, mg; Sp——Dust catchment area of ​​the white porcelain plate, m2.
Additional notes:
This standard was proposed by the Rolling Bearing Industry Standardization Technical Committee and is under the jurisdiction of the Luoyang Bearing Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Hangzhou Bearing Test Research Center. The main drafters of this standard are Xue Jin and Sheng Xianxi. 6
（A1)
People's Republic of China
Mechanical Industry Standard
Rolling Bearings
Cleanliness and Assessment Method
JB/T 70501993
Published and issued by the China Academy of Mechanical Science
Printed by the China Academy of Mechanical Science
(No. 2 Shouti South Road, Beijing
Postal Code 100044)
Format 880×12301/16
Sheet 5/8Number of words 12.000
First edition in May 1994
First printing in May 1994
Print run 1-500
Price 6.00 Yuan
Mechanical Industry Standard Service Network: http://www.JB.ac.cn
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