This standard specifies the type, size, technical requirements and inspection of brake pads for block brakes. This standard applies to brake shoes for block brakes. JB/T 7021.2-1993 Block brake shoe JB/T7021.2-1993 Standard download and decompression password: www.bzxz.net

Machinery Industry Standard of the People's Republic of China
Block Brake
Subject Content and Scope of Application
Brake Shoes
JB/T 7021.2---93||tt| |This standard specifies the type, size, technical requirements and inspection of brake pads (including assemblies) used in block brakes. This standard applies to brake pads for various block brakes, 2 referenced standards
GB9439 gray cast iron parts
JB/T7021.1 block brakes
Connection dimensions|| tt||JB/T7021.3 block brake
brake pad
3 types and sizes
3.1 type
3.1.1 brake pads according to their The connection method with the brake pad is divided into: a.
bonded brake pad, its type code is A; b.
c.
riveted brake The type code of pad + is B; the type code of assembled brake pad is C. 3.1.2 Brake pads are divided according to their materials:
a. Cast-iron brake pads, their codes are represented by 1 b.
Cast iron (steel) brake pads, their codes Represented by 2. 3.2 Dimensions
3.2.1 The dimensions of the brake pads should comply with the requirements in Figure 1 and Table 1. The structure may not match the illustration. 3.2.2 The location and dimensions of the rivet holes of the riveted brake pad are shown in Figure 2 and Table 2. 3.2.3 The location and dimensions of the screw holes of the assembled brake pad are shown in Figure 3 and Table 3. The Ministry of Machinery Industry of the People's Republic of China approved 168
1994-07-01 and implemented on 1993-09-21
D
160
200
250|| tt||315
400
500
630
710
800
70
90||tt| |110
11
140
180
225
255
280
Braking Village View||tt ||JB/T 7021.2—93
brake wheel
Ya Shang
x
EE
Type 2
dz|| tt||(H9)
16
20
25
30
35
40
45|| tt||50
55
Note: The tolerance of the axis matched with d is d9.
e
115
140
170
212
260
320
390|| tt||440
510
Country
A
Type 1
Figure 1
Table 1
g| |tt||(h11)
65
65
80
100
125
160
200| |tt||224
260
(H11)www.bzxz.net
35
35
40
50
62| |tt||80
100
112
130
29
32
37
44.5||tt ||50
58
63
70
95
Parallelism Tolerance
0.1
0.15||tt ||0.2
g2
23
24
29
34.5
40
46
51
80
mm
(max)
20
25
28
35
40
40
48
52
169
n60,200
D=250
D315||tt ||JB/T7021.2—93
n=400
D= 500
Xiapu
t
The diameter of all rivet holes is 8.2mm
Figure 2
Table 2
D
160
200
250
315
400
500
630
710
800
r
25°
28
31°
p
13°
21°
Note: Use GB875--86 "Flat Head Semi-Hollow Rivet" (colored). 170
aa
115
h
15
20
40
75
90| |tt||105
120
=630
25
30
D=710.800
mm
rivet Number
5
8
12
18
24
Plate
D =260:30||tt ||nixMd
a.
Dimension C in the picture is the brake pad thickness.
D
160
200
250
315
400
500
630|| tt||710
800
m
20
25
28
35
40||tt| |48
52
ha
8
10
12
14
16
6
12
14
16
JB/T7021.2---93
D=400,500
nixMd||tt| |Bo Yaofu
a
t
Figure 3
Table 3
a
D=630, 710, 800|| tt||n,xMd
+·+
2
20
25
30
45
14
16
Note: ① Bolts are selected according to GB5782-86 "Hexagonal Head Bolts". ② The spring washer is selected according to GB93-87 standard push spring washer 55
78
90
105
25
30
40
8
bolt hole Md
M8
M10
M12
M16
③ Tensile strength of pressure plate Do not dry dry 08F steel 3.3 model and marking in GB711--88 "High-quality carbon cold structural steel hot-rolled thick steel plate and wide steel strip"
3.3.1 model expression method
mm||tt ||Screw hole depth
20
25
30
40
173
3.3.2 Marking example
JB/T 7021. 2.--. 93
Village pad code (marked only on the assembly)
Brake wheel diameter D, mtn
Product code (see Article 3.1)| |tt||The brake wheel diameter L) is 400mm, and the aluminum brake pads are bonded, marked as: brake pad A1-400JB/T7021.2
The brake wheel diameter D is 4Q0mm, With riveted brake pads, iron brake pads, marked: brake pads B2-400EJB/T7021.2
4Technical requirements
4.1 The materials of various types of brake pads should generally be no less than HT200 in GB9439. For special occasions, cast aluminum, steel plates, forged steel, cast steel or ductile iron can be used, and the tensile strength of the materials should be no less than 360N/mm2 . 4.2 The pin hole of the aluminum brake pad (type 1) must be equipped with a steel sleeve. 4.3 In addition to meeting the dimensional requirements of Article 3.2, the structure of the brake pad, including all connecting parts of the brake pad, should be able to ensure the effective wear thickness of the brake pad (1/2 of the total thickness).
4.4 For brake pad assemblies with brake pads, the brake pads used shall comply with the provisions of JB/T7021.3, and purchased parts shall have certificates of conformity. 4.5 The fitting area between the brake pad assembly and the brake wheel should not be less than 60% of the design area, and should reach 70% after grinding. 4.6 The assembly gap between the inner arc surface of the brake pad and the brake pad should not be greater than 0.5mm at any place. 4.7 The brake shoe assembly should operate under a static torque condition that is no less than 1.25 times the maximum rated braking torque value corresponding to the matching brake wheel diameter. There must be no permanent deformation that affects the braking performance, such as deformation of the shaft hole or rivet hole, shearing or deformation of the rivet, cracking of the bonding surface, deformation and loosening of the pressure plate, misalignment of the brake lining and brake pads, etc. 5 Test method
Install the brake pad assembly under test on the specified test device (see Figure 4), then apply force F to reach half of 1.25 times the rated torque, and then press the brake wheel. Corresponds to the motor speed operation. Test 5 times, each operation time shall not be less than 5$, and shall meet the provisions of Article 4.7, and the brake lining shall be in good condition without damage or delamination. The brake lining shall be allowed to have slight cracks, but shall be firmly attached. Attached to the brake shoes. When this test is carried out on the brake inertia test bench, the number of tests is 3 times 2
F
1 hinge point; 2-brake pad ring; 3 brake wheel; 4-- Rigid frame Figure 4
172
6 Inspection rules
6.1 Factory inspection
JB/T 7021.2--93
6.1.1 Each brake Before leaving the factory, the tiles or main rings should be inspected by the manufacturer's inspection department in accordance with this standard and product drawings. Only those tiles or general rings that pass the factory can be shipped out. Products leaving the factory must be accompanied by a certificate of conformity. 6.1.2 Factory inspection items
Factory inspection items include:
The structure shall be in accordance with the requirements of Articles 4.2 and 4.3; a.
The brake pad assembly clearance shall be in accordance with Article 4.3. In accordance with the requirements of Article 4.6, use a feeler gauge to inspect; b.
brake pads shall be inspected in accordance with the requirements of Article 4.4. 6.2 Type inspection
1 Type inspection must be carried out when one of the following situations occurs: 6.2.1
During the trial production of new products and the finalization appraisal of old products transferred to factory production: a.
b.
c.
d.
e.
When there are changes in structure, process or materials that may affect product performance: When the product has been discontinued for more than one year and resumes production ; When the national quality supervision agency proposes a requirement for type inspection; mass-produced products should undergo type inspection once a year. 6.2.2 Type inspection items
In addition to all items of factory inspection, the type inspection items should also be inspected for the following items: Material inspection, carried out in accordance with the requirements of Article 4.1, and the materials used for the brake pads should have certificates , and sample inspection should be carried out; a.
Assembly contact area inspection, according to the requirements of Article 4.5, use the coloring method for visual inspection, and fit the assembly on the standard brake wheel for inspection b.|| The static moment test of tt||1.25 times shall be carried out according to the method in Chapter 5. When the new product is finalized and identified, it must be inspected on the inertial test bench.
6.2.3 The sampling method for type inspection is based on the order of the size of the production specifications of each type. One type will be selected from every two types. If there are less than three types, one type will be selected, but no more than three types will be selected at most. Draw 3 pairs. 6.3 Judgment Rules
All inspection items of the product must be qualified. If there are unqualified items, it is allowed to double the sampling and re-inspect the unqualified items several times. All the unqualified items must be qualified during the re-inspection.
Additional notes:
This standard is proposed and administered by the Beijing Hoisting and Transport Machinery Research Institute of the Ministry of Machinery Industry. This standard is drafted by Jiaozuo Brake Factory. The main drafters of this standard are Chen Guangming, Wang Zhifang, Bai Jie and Liu Wusheng. 173
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