SJ 20591-1996 General specification for synchronous toothed belt drive mechanisms for radar control systems
Some standard content:
Military Standard of the Electronic Industry of the People's Republic of China FL3030
Used in Radar Control Systems
SJ 20591-1996
General Specification for Synchronous Belt Drives Used in Radar Controlling System
(Draft for Approval)
1996-08-30 Release
Approved by the Ministry of Electronics Industry of the People's Republic of China Implementation on January 1, 1997
1. Scope
1.1 Subject matter
1.2 Scope of application
1.3 ClassificationbzxZ.net
2 Reference documents
3 Requirements
3.1 Qualification
3.2 Materials
3.3 Design
3.4 Structure
3.5 Standard parts
3.6 Performance characteristics
3.7 Environmental requirements
3.8 Lifespan|| tt||4 Quality Assurance Provisions
4.1 Inspection Responsibility
4.2 Inspection Classification
4.3 Inspection Conditions
4.4 Identification Inspection
4.5 Quality Consistency Inspection
4.6 Inspection Methods
5 Delivery Preparation
5.1 Marking and Packaging
5.2 Transportation
5.3 Storage
6 Notes·····
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6.1 Intended use
+中電專+++-中
6.2 Definition
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Appendix A Calculation of rated power and design power of synchronous belt drives (reference) (21)」Scope
People's Republic of China Electronic Industry Military Standard SJGeneral specification for
synchronous belt drives used in radar rontrolling sygtem
1.1 Subject content
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This specification specifies the main contents of the design, structure, performance characteristics, quality assurance regulations, etc. of the synchronous belt drive mechanism (hereinafter referred to as synchronous belt drive). 1.2 Scope of application
This specification is applicable to synchronous belt drives for various radar control systems. This specification is also applicable to light-load, motion-transmitting intermittent belt drives in military electronic equipment.
1.3 Classification
The intermittent belt drives specified in this specification adopt single-sided tooth synchronization. The available models are MXL, XXL, XL, L Four categories.
2 Reference documents
GB11616—89 Synchronous belt dimensions
9 Pulley material, surface roughness and balance GB11357--89
GB11362—89 Calculation of rated power and center distance of synchronous belt transmission GJB150.1—86 Environmental test methods for military equipment GJB150.3—86 Environmental test methods for military equipment Issued by the Ministry of Electronics Industry of the People's Republic of China in 199×-××-×× General provisions
High temperature test
199x-×× implementation
GIB150.4-86 Environmental test method for military equipment Low temperature test
GJB150.5---86 Environmental test method for military equipment Temperature shock test
Wet heat test
GJB150.9-86 Environmental test method for military equipment GIB150.16-86 Environmental test method for military equipment Vibration test GJB150.18--86 Military equipment environmental test method God attack test
GJBI79--86 Count sampling inspection procedures and tables Synchronous toothed belt drive for radar control system Structural type SIx × × x --x ×
Type, size series
3 Requirements
3.1 Qualification appraisal
The synchronous belt drive submitted according to this specification shall be a qualified product or a product approved for finalization. 3.2 Materials
The synchronous belt uses rubber (including polyurethane elastomer) as backing rubber and tooth rubber tensile body. The core rope used shall be glass fiber rope, steel wire rope or synthetic fiber rope, etc., and its twist shall be uniform. The tooth cover cloth shall be nylon cloth or other fabrics (polyurethane belt has no cover cloth), and the density of its warp and weft shall be uniform. The synchronous belt pulley and pulley retaining ring can be made of steel, aluminum alloy, other suitable alloys or engineering plastics. The materials of other parts are also selected according to the corresponding standards.
3.3 Design
3.3.1. Reference rated power
The reference rated power refers to the rated power when the belt width is the reference width. The reference rated power P. can be calculated according to formula (1) and formula (2); it can also be found from Table A3 to Table A6 in Appendix A according to the speed and number of teeth of the small pulley.
= (T- . ..
Where: P. Basic thrust rated power, W;
P—-the pitch of the teeth of the belt and the pulley, mm:
2-the number of teeth of the small pulley
the speed of the small pulley, r/min;
T. The allowable working tension when the belt width is the reference width b, N: T. ... The centrifugal force when the belt width is the reference width 6, N; m-the mass per unit length of the belt when the belt width is b, kg/m; v belt speed, m/s
The allowable working tension T of various belt types and the mass per unit length 1m are shown in Table 1. Table 1
Synchronous belt model
Allowable working tension,
Mass per unit length m
The reference width of the belt refers to the maximum width of the standard belt with a pitch of P: the reference width of various belt types should comply with the provisions of Table 2. Table 2
Synchronous belt model
3.3.2 Selection of belt type
Reference width bso
Based on the design power P and the small pulley rotation II, select the belt type according to Figure 1; when the selected type is close to the adjacent type, the two types of belts should be designed in parallel, and the selection should be made according to the design power P and the small pulley rotation II. 3
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Preferred.
3.3.3 Transmission Center
The transmission center distance A of the synchronous belt shown in Figure 2 is calculated according to formula (3) and formula (4): ny,t/min
Figure 1 Synchronous belt selection diagram
Figure 2 Transmission center distance calculation
2πcoso
(z, z,)
SMIPaw
In the formula: A
The transmission center distance between the two pulleys, mm
The pitch of the teeth of the belt and the pulley, mm;
2,—The number of teeth of the small pulley;
22—The number of teeth of the large pulley;
z,The number of teeth of the belt;
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invo=tgo-o, the value of α can be found by looking up the involute function or using the step-by-step approximation method.
When the value of Z/Z, is close to 1, the transmission center distance should be calculated according to formula (5) and formula (6): A~ M+ / M_![P,2,-2]
3.3.4 Synchronous belt length
The synchronous belt length is calculated according to formula (7):
L = 2AcoS(+
n(d,+ d,)
Where: L, synchronous belt length, mm,
A transmission center distance, mm;
tp(d, d,)
d, small pulley pitch circle diameter, mm;
d, large pulley pitch circle diameter, mm;
.Pi.-..
The calculated belt length should be selected according to the provisions of SJX××× to select the closest standard belt length.
3.3.5 Number of meshing teeth of small pulley
The number of meshing teeth Z of small pulley Z is calculated according to formula (8)P
3.3.6 Minimum number of teeth on small pulley
To avoid too few teeth between the belt and pulley, the number of teeth on the small pulley should be greater than the minimum number of teeth specified in Table 3,
Small pulley speed nl
≤900
900～<1200
1200～<1800
1800～≤3600
3600~4800
Synchronous belt model| |tt||Minimum number of teeth on the small pulley
For the design calculation method and steps of synchronous belt transmission, please refer to Appendix A (reference) of GB11362
3.4 Structure
3.4.1 Pulley retaining ring
Pulley retaining ring can be selected according to the following different situations 3.4,1,1 In a two-axis transmission, one of the three pulleys must have a retaining ring on both sides, or two pulleys have a retaining ring on different sides. 3.4.1.2 In a transmission with a center distance of more than 8 times the diameter of the small pulley, both sides of the two pulleys should have retaining rings.
3.4.1.3 In vertical shaft transmission, one pulley should have retaining rings on both sides, while the other pulleys only have retaining rings on the bottom side
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3.4.1.4 In multi-axis transmission, it should be ensured that every other pulley has two retaining rings, or each pulley has a retaining ring on the opposite side
3.4.1.5 The size and structure of the pulley retaining ring shall comply with the provisions of SJ××××. 3.4.2 Pulley installation and adjustment
When installing the pulley, the transmission center planes of the two pulleys should be located in the same plane, the parallelism of the belt axis must be ensured, and the pulley deflection angle should be adjusted (see Figure 3)) to make t6/1000.
Figure 3 Pulley alignment
3.4.3 Use and installation of tensioning wheel
3.4.3.1 Use of tensioning wheel
a. When the center distance of the transmission mechanism cannot be adjusted, it is used as a method to tension the toothed belt.
b. In a transmission with a larger speed ratio, it increases the wrap angle of the small pulley. 3.4.3.2 Installation of tensioning wheel
a. Installed on the inside, used for tensioning the toothed belt. In this case, the tensioning wheel should be a toothed belt pulley. When the number of teeth on the tensioning wheel is greater than the minimum number of teeth on the pulley, in order to avoid reducing the number of meshing teeth, the tensioning wheel should be installed on the loose side of the belt (see Figure 4a). b. Installed on the outside: used to increase the wrap angle of the pulley. At this time, the tensioning wheel can be a flat pulley without a protrusion in the middle. Its diameter is the diameter of the pulley with the least number of teeth, and it should be installed on the loose SJ
side so that the belt will not produce excessive bending (see Figure 4b). Strong tensioning wheel
Figure 4 Installation of tensioning wheel
3.4.4 Chassis
System steam wheel
To ensure that the synchronous belt transmission mechanism works normally under conditions such as sand, dust, rain, salt spray, and mildew, it can be made into a closed chassis alone or installed in a closed control system chassis, and pay attention to maintainability.
3.5 Standard parts
Standard parts should be used to the maximum extent in the synchronous belt transmission mechanism, and should be selected from the existing national standards and national military standards. 3.6 Performance characteristics
3.6.1 Pulley
The tooth shape, size and shape and position tolerance of various types of pulleys used in the transmission mechanism shall comply with the provisions of SJ××××. 3.6.2 Synchronous belt
3.6.2.1 The belt length and limit deviation, belt width and limit deviation of various types of synchronous belts used in transmission mechanisms shall comply with the provisions of SJX×××. 3.6.2.2 The breaking force of various types of synchronous belts shall comply with the provisions of Table 4. SJ
3.6.2.3 The constant load elongation of various types of synchronous belts shall not exceed 4%. The constant load elongation is calculated according to formula (9):
1241:84
武中: 1-Original length of synchronous belt: mm;△l-Elongation length of synchronous belt when constant load is applied, mm;-Elongation, %
When measuring the constant load elongation of various types of synchronous toothed belts, the applied constant load shall be in accordance with the provisions of Table 4.
Synchronous belt model
Belt width code
3.6.3 Tensioning of synchronous belt
Breaking force
Standard load
In synchronous belt transmission mechanism, the synchronous toothed belt must have appropriate tension when installed. The tensioning of synchronous toothed belt can be achieved by adjusting the center distance of the transmission mechanism; it can also be achieved by installing a tensioning wheel. The tensioning degree of synchronous toothed belt can be adjusted within the span of two hunting wheels.
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