JB/T 3721-1999 This standard is a revision of JB 3721-84 "Disc brake shoes for mine hoists". The main technical content change is to directly quote Appendix A in the original standard in the friction performance test method, calculation and record. This standard specifies the model, specification, technical requirements, test methods, inspection rules, marking, packaging, transportation and storage of disc brake shoes for mine hoists. This standard is mainly applicable to disc brake shoes for mine hoists. Brake shoes are used for braking or deceleration of mine hoists. JB/T 3721-1999 Disc brake shoes for mine hoists JB/T3721-1999 Standard download decompression password: www.bzxz.net

ICS73.100.40
Machinery Industry Standard of the People's Republic of China
JB/T3721-1999
Mine Hoist
Disc Brake Shoes
Brakepadforminehoistwinderdiscbrakes1999-06-28 Issued
National Machinery Industry Bureau
2000-01-01 Implementation
JB/T3721—1999
This standard is a revision of JB3721—84 "Disc Brake Shoes for Mine Hoist". Compared with JB3721—84, the main technical content change of this standard is to directly quote Appendix A in the original standard in the friction performance test method, calculation and record.
This standard replaces JB3721—84 from the date of implementation. This standard is proposed and managed by the National Technical Committee for Standardization of Mining Machinery. The responsible drafting unit of this standard is CITIC Heavy Machinery Company. The main drafters of this standard are Pei Yulan, Tian Min, Bi Yuhua, Cai Jingying and Guo Ming. 1 Scope
Machinery Industry Standard of the People's Republic of China
Brakepad for mine hoist winder disc brakes
Brakepad for mine hoist winder disc brakesJB/T3721-1999
Replaces JB3721-84
This standard specifies the model, specification, technical requirements, test methods, inspection rules, marking, packaging, transportation and storage of disc brake shoes for mine hoist winder.
This standard is applicable to disc brake shoes for mine hoist winder. Brake shoes are used for braking or deceleration of mine hoist winder. 2 Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are all valid. All standards will be revised, and the parties using this standard should explore the possibility of using the latest version of the following standards. GB/T57651986 Friction material impact strength determination method JB/T16041998
3 Models and specifications
Mining machinery product model compilation method
3.1 The brake shoe model representation method shall comply with the provisions of JB/T1604. z
Manufacturer number
Brake shoe (brake)
Mine hoist (mine)
3.2 The brake shoe size shall be determined by negotiation between the manufacturer and the user. 4 Technical requirements
4.1 The test disc material is 16Mn steel plate, the surface roughness R, value should be less than 1.6μm, its hardness is 150~160HB, and the test specific pressure is 0.98MPa. When the friction speed at the center of the specimen is 7.5m/s, the friction coefficient and wear rate of the brake shoe shall meet the requirements of Table 1. 4.2
Brake shoe impact strength shall not be less than 30.38N·cm/cmz. Brake shoe hardness shall be less than 490.5Nmm2.
National Machinery Industry Bureau approved on 1999-06-28 Friction coefficient
Wear rate
10~cm/(Nm）
≤245
≤678
Implemented on 2000-01-01bzxz.net
Reduced from 250 to 100
1 Temperature error is ±5℃.
2 Friction coefficient and wear rate are assessed at the same time, JB/T3721-1999
Table 1 (end)
Friction coefficient u
Brake shoe oil absorption rate and water absorption rate should be less than 1% within 4h4.4
Brake shoe is not allowed to scratch or scratch the test plate, and no sparks are allowed to appear in the dark room. Wear rate
10cm/N·m)
≤883
The parallelism error between the working surface of the brake shoe and the matching surface of the lining plate should be less than 0.3mm/1000mm. The flatness error value of the matching surface of the brake shoe and the lining plate should be less than 0.4mm when the area is 400mm×400mm4.7
Brake shoe is not allowed to have cracks, blistering, delamination and inclusions that affect the use of the pressing defects. 5 Test method
Friction performance test
5.1.1 The test equipment is MD-240 fixed speed friction tester. 5.1.2 Test conditions:
a) The friction surface of the test disc is not allowed to have scratches that affect the test; b) Test piece size 20%mm×30mm×8mm
) Test temperature (see Table 1) is mainly heated by friction heat, and auxiliary heaters can be used when necessary; d) Test time, 5000 revolutions or 10.5 minutes at each specified test temperature. 5.1.3 Test method:
a) Running-in: Running-in temperature ≤ 100℃, contact area ≥ 95%sb) Determination of specimen thickness: two to three points:
c) Test procedure: Carry out the test at each temperature in turn for 5000 revolutions (error ± 50 revolutions) or 10.5 minutes. The specified temperature must be reached at 150 revolutions or within 3 minutes. The friction force is measured and recorded at 2500 revolutions (error ± 100 revolutions), 3500 revolutions (error ± 100 revolutions) and 4500 revolutions (error ± 100 revolutions) or at 5 minutes, 7 minutes and 9 minutes. The friction force should be read when the temperature reaches a stable level during the slow heating process:
d) Determine the thickness of the test piece after each temperature specification test. The thickness measurement after the test needs to be carried out after the test piece cools to below 50℃. 5.2 Calculation and record
a) Calculation of friction force and friction coefficient:
Where: F average total friction force, N:
F=f+f,+f
fi, f2, f—total friction force measured at 5min, 7min, and 9min, N;——friction coefficient;
P—total pressure (normal force), N.
b) Calculation of wear volume and wear rate:
JB/T3721—1999
AV=A(h-ha)
V=△V /(SF)= A(hm-h)/(2元RnF)Where: △V-wear volume, cm:
Specimen area, A-12cm2 (take two specimens, the area of ​​each specimen is 2×3-6am2); h measures the specimen thickness before the test, cm:
-sample thickness after the test, cm;
wear rate, 10-7m3/(N·m);
S-friction distance, cm:
Faverage friction force, N:
R-distance between the center of the specimen and the center of the spindle, R-15cm; test speed, r/min.
Substituting the above values ​​into the formula, we get the following wear rate calculation formula: V=2.54×1000xAh/F
Wherein: Ah-wear thickness, mm.
5.3 The impact strength shall be determined in accordance with the provisions of GB/T5765. 5.4 Determination of oil absorption and water absorption
5.4.1 Sample size: (45mm±1mm)×(45mm±1mm)×(5mm±0.2mm). 5.4.2 Test equipment and tools:
a) Analytical balance (accuracy 0.001g);
b) Vernier caliper (accuracy 0.05mm);
c) Micrometer (accuracy 0.01mm);
d) Container, tweezers, filter paper, etc.
5.4.3 Test method
5.4.3.1 The test is carried out at room temperature. The arbitration test is required to be carried out at 20℃±5℃. 5.4.3.2 The test surface needs to be polished with No. 1 sandpaper. The surface should be clean and free of defects such as cracks and sand holes. w.
5.4.3.3 Measure the size of the sample with a vernier caliper or micrometer. After weighing on the balance, immerse the sample in distilled water or No. 10 automotive lubricating oil. The samples should not touch each other or stick to the container wall in the liquid. There should be no bubbles on the surface of the sample. 5.4.3.4 After 4 hours in the liquid, take out the sample and carefully wipe the water or oil on the surface of the sample with filter paper until there is no water or oil stain on the surface of the sample and the filter paper. Weigh it immediately. The time should not exceed 2 minutes. The water absorption rate or oil absorption rate B is calculated as follows:
Wherein: W—weight of the sample before immersion in water or oil, g: weight of the sample after immersion in water or oil, g.
6 Inspection rules
JB/T3721-1999
The parallelism error of the two surfaces of the brake shoe shall be inspected by a three-level flat plate and a measuring stand with a micrometer. 6.2 The parallelism error of the matching surface of the brake shoe and the lining plate shall be inspected by a three-level flat plate and a measuring stand with a micrometer. 6.3 Brake shoes of the same variety, specification and material are counted as a batch of 100 pieces or one batch. Those less than 100 pieces are also counted as a batch. 6.3.1 The manufacturer must inspect the appearance and size of each product in a batch. 6.3.2 Take one brake shoe at random from each batch for the following tests: a) Friction coefficient and wear rate determination: Take four samples at different positions of a brake shoe and conduct the test twice; b) Impact strength determination: Take five samples at different positions of a brake shoe for inspection; ) Brinell hardness determination: Take three samples at random from a brake shoe for inspection; d) Water absorption and oil absorption determination: Take three samples for each item for inspection, and inspect once a month. 6.3.3 Take the arithmetic mean of each test as the test result. 6.4 If any technical index of the sample does not meet the technical requirements after inspection, double sampling should be carried out and the index should be re-inspected. If it is still unqualified, the batch of brake shoes will be treated as unqualified. 7 Marking, packaging, transportation and storage
7.1 Each brake shoe and lining surface should be printed with a mark, which includes: manufacturer name, product name, batch number, inspection date and inspection personnel number, etc.
7.2 The outside of the packaging box should be marked with:
a) Manufacturer's name, trademark and address:
b) Product name and mark:
c) Receiving unit and address;
d) Number of pieces;
e) Gross weight:
f) "Handle with care", "Moisture-proof" and other marks: g) Date of manufacture.
7.3 The brake shoe should be sealed with a plastic bag first and then firmly packed into a dry and sturdy box to ensure that it will not be damaged during transportation. Each box should contain products of the same specification and its weight should not exceed 25kg. 7.4 The packaging box should be accompanied by a product certificate, which includes the following: a) Manufacturer's name:
b) Product name and mark:
c) Number of pieces;
d) Manufacturing date:
e) Signature and seal of the technical inspection department.
7.5 Brake shoes should be stored in a dry, ventilated and flat place and should not come into contact with grease, water or other substances that affect friction performance. 4
Mechanical Industry Standard
Disc brake shoes for mine hoists
JB/T3721-1999
Published and distributed by the Mechanical Standardization Research Institute of the Ministry of Machinery Industry Printed by the Mechanical Standardization Research Institute of the Ministry of Machinery Industry (No. 2 Shouti South Road, Beijing: Postal Code 100044)*
Book size 880×1230
Sheet 1/2
Word count 10000
First edition in July 1999
First printing in July 1999
Print count 1-500
Price 500 yuan
99-148
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