Some standard content:
GB9745-1995 | | tt | |tt|| Chapter: New Tires" and the US Federal Aviation Administration Technical Standards TSO-C62d "Aviation Tires" (1990 edition) revised GB9745-88.
Because ISO3324/1-1993 only stipulates the marking and size matching of aviation tires, therefore, when this standard is revised, this aspect is equivalent to the international standard. In order to meet the airworthiness needs of civil aviation products and in accordance with the relevant national civil aviation management regulations, this standard also adopts the US Federal Aviation Administration technical standards TSO-C62d "Aviation Tires" (1990 edition) in terms of aviation tire performance indicators. ). At the same time, some contents in GB9745--88 that have been proven to be suitable for my country's conditions without hindering international applicability have been retained. This standard will replace GB9745-88 from the effective date. This standard is proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the Shuguang Rubber Industry Research Institute of the Ministry of Chemical Industry. This standard was drafted by: Shuguang Rubber Industry Research Institute of the Ministry of Chemical Industry. The main drafter of this standard is Sheng Baoxin, Zhang Qingzeng and Wang Huining Www.bzxZ.net
This standard was first released in September 1988.
1 range
National Standard of the People's Republic of China
Aviation
Wheel
Tire
Aircraft tyre
GB9745-1995
Replaces GB9745-88
This standard specifies the technical requirements, test methods, inspection rules, marking, packaging, use and storage requirements for aviation tires (hereinafter referred to as tires),||tt ||This standard applies to all types of civil aviation tires. Referenced standards
2
The provisions contained in the following standards constitute provisions of this standard through reference in this standard. The editions shown were valid at the time of publication of the standard. All standards are subject to revision and parties using this standard should explore the possibility of using the latest version of the standard listed below. Determination of tensile properties of vulcanized rubber and thermoplastic rubber GB/T528--92
GB/T6326-94
Tire terminology (neqISO3877/1:1978, neqIS()4223/1:1989) GB/ T9746—1995
GB/T11191--89
GB/T11192—89
GB/T11193—89
GB/T11194—89
GB /T13652—92
GB/T13653—92
GB/T13654-92
GB/T13655-92
GB/T13656—92
HG2195 —91
3 definition
Aviation tire series
Aviation tire burst pressure test method (neqIS()3324/2:1979) Aviation tire static load performance test method (neqISO3324/2: 1979) Aeronautical tire outer edge size measurement method (neqIS) 3324/2: 1979) Aeronautical tubeless tire air tightness test method (neqISO3324/2: 1979) Aeronautical tire surface quality
Aeronautical tire X-ray detection method | |tt||Aviation tire holographic testing method
Aviation tire static balance difference test method
Aviation tire physical property testing method
Aviation tire use and maintenance
this The standard adopts the following definitions.
3.1 Maximuminflatedtyredimensions refers to the tire installed on the specified rim inflated to the rated inflation internal pressure, parked at room temperature for at least 12 hours, and then adjusted to the rated inflation internal pressure. The size of the corresponding part of the tire. 3.2 Low-speed tires low-speedtyre
tires with a rated speed less than or equal to 193km/h. 3. 3
High-speed tire high-speed tire
Tires with a rated speed greater than 193km/h. | |tt | 4 Technical requirements
4.1 Specifications and dimensions
GB9745-1995
4.1.1 Specification expressions and new tire inflation dimensions should comply with the regulations of GB/T9746. 4.1.2 In addition to the provisions of GB/T9746, the maximum shoulder size of the tire should be determined according to formula (1) and formula (2): Ws=0.9W
Hs-0.9H.
where : Ws--maximum shoulder width of pneumatic tires; W-maximum section width of pneumatic tires:
Hs-maximum shoulder height of pneumatic tires;
H-maximum section height of pneumatic tires.
Note: The maximum cross-sectional width includes the raised height of the logo, anti-scuff line and decorative line on the sidewall, but does not include the height of the front wheel tire's water-conducting rubber rib. 4.2 Materials
Tire materials should meet the expected requirements, and the suitability of the materials should be determined based on sufficient experience in use or dynamic tests. 4.3 Rating value
4.3.1 Rated load
(1)
(2)
4.3.1.1 The rated load of tires should comply with the regulations of GB/T9746. 4.3.1.2 Tires certified in accordance with the provisions of this standard can also be used on helicopters. The maximum rated load is determined by multiplying the rated load of normal tires by 1.50, and the inflation internal pressure is correspondingly increased by 1.50 times without any additional qualification tests. 4.3.2 Rated inflation internal pressure
The rated inflation internal pressure of the tire shall comply with the regulations of GB/T9746. 4.3.3 Load radius
The nominal load radius of the tire should comply with the regulations of GB/T9746, and the values ??of its nominal load radius, nominal load radius tolerance and actual load radius should be determined.
4.4 Temperature requirements
4.4.1 Environment
Use appropriate tests or analyzes to prove that tire materials are exposed to ambient temperatures of not higher than -40°C and not lower than 71°C respectively After at least 24 hours, its physical properties should not be lower than the design requirements. 4.4.2 Rim heat
Use appropriate tests or analyzes to prove that the physical properties of tire materials should not be lower than those specified in the design after being exposed to a rim heat temperature of not less than 150°C for at least 1 hour.
Low speed tires or front tires may be tested or analyzed at the highest rim thermal temperature expected during normal use. 4.5 Dynamic performance
Tires after dynamic testing in accordance with the provisions of this standard shall comply with the following requirements: 4.5.1 Except for the overload take-off test, the tires after the test shall not show any structural damage other than normal wear and tear. 4.5. 2 After the overload take-off test, the air tightness of the tires should remain good. The drop rate of the inflation internal pressure within 24 hours should not be greater than 10% of the inflation internal pressure at the beginning of the test.
After the overload takeoff test, the tire tread is not required to be intact. 4.5.3 When conducting dynamic simulation tests in accordance with the provisions of this standard, during the first five tests, there should be no rotation between the test tire bead and the rim: such rotation should not damage the bead air tightness of the tubeless tire in subsequent tests. Layer or inner tube tire tube or valve. 4.6 Overpressure
Under the ambient temperature and not less than 4.0 times the rated inflation internal pressure, the tire should be able to maintain at least 35. 4.7 Air holes
GB9745-1995
Tubeless tires or For inner tube tires with an inflated internal pressure higher than 686kPa, air holes should be punctured at the positions specified in the design drawings. The depth of the holes must not reach the inner liner of the tubeless tire. The surface of the vent holes is indicated by white dots. 4.8 Air tightness of tubeless tires
The air tightness of tubeless tires should meet the following requirements: install the tubeless tire on the specified rim, inflate it to the rated inflation internal pressure, and park it at room temperature for at least 12 hours. If the air pressure drops, replenish it to the rated inflation internal pressure. After parking at room temperature for at least 24 hours, the drop rate of the inflation internal pressure should not exceed 5% of the rated inflation internal pressure. 4.9 Surface quality
The surface quality of tires should comply with the regulations of GB/T13652. 4.10 Weight
The weight of the tire should meet the design requirements.
4.11 Internal defects
Non-destructive inspection of tires should be carried out in accordance with the provisions of this standard, and the inspection results should comply with 6.5 regulations. 4.12 Static balance difference
Tires should be 100% inspected for static balance difference. The maximum static balance difference M should not exceed the calculated value of formula (1): M=0.00274D2
Where: M——the specified static balance difference value of the tire, N·cm; D——the maximum inflated outer diameter of the tire, cm. When the measured static balance difference value exceeds the calculated result of the above formula, the tire should be patch balanced. 4.13 Balance mark
....(1)
A red dot should be marked on the sidewall of the tire close to the bead at the light spot as a light spot mark. This mark should remain legible during the storage life of the tire and the life of the original tread compound.
4.14 Physical properties
The physical properties of tire materials should comply with design regulations. 4.15 Storage and Use Period
Tires are stored in accordance with HG2195 regulations, and their storage and use period is five years from the date of manufacture. 5 Test methods
5.1 The measurement of tire size shall comply with the following regulations: 5.1.1 The maximum inflated size shall be measured according to GB11193. 5.1.2 For tires without shoulder points, the shoulder size shall be measured as follows: 5.1.2.1 Install the tire on the test rim, inflate it to the rated inflation internal pressure, and park it at room temperature for at least 12 hours. If the air pressure drops, replenish it to the rated inflation internal pressure and wait for at least 10 minutes before measuring. 5.1.2.2 Based on the maximum shoulder width W of pneumatic tires specified in this standard, determine two points A and A' on the outer contour of the tire that are symmetrical to the tread centerline. The line connecting these two points should be parallel to the tire axis. Use the same method to determine the two symmetry points B and B' of A and A' relative to the tire axis. Measure the vertical distance between points A and B, and A' and B' respectively to obtain the measured shoulder diameter of the tire. The measurement result is the arithmetic mean of two sets of data that are 90° apart around the tire circumference. When the measurement result is less than or equal to the shoulder diameter of a pneumatic tire specified in this standard, the maximum shoulder size of the tire is qualified, otherwise it is unqualified.
5.2 Tire temperature requirements are tested as follows: 5.2.1 Environment
Cut the tire tread samples. In the test chamber where the temperature is not higher than -40℃ and not lower than 71C respectively Expose for at least 24h. Then measure the tensile strength and elongation at break according to GB/T13656 (the cutter can be specified as needed). 5.2.2 Rim heat
GB9745-1995
Take the semi-finished rubber material with rubber attached to the bead wrapper and vulcanize it according to the tensile test regulations in GB/T528 (the cutter can be specified separately as needed) into test piece and park. After cutting into specimens, expose them to a test chamber with a temperature not lower than 150°C for at least 1 hour. After taking them out, place them in a standard laboratory environment for 4 to 96 hours, and measure their tensile strength and elongation at break. 5.3 The dynamic performance of tires shall be tested as follows: The tires shall pass the dynamic test specified in this article. The tires after the test should not show any structural damage other than those specified in Article 4.5 and normal wear and tear.
5.3.1 General
The following conditions apply to the dynamic tests of both low-speed and high-speed tires. 5.3.1.1 Tire test load
Except for the special tests specified in this standard, the test load of the tire at the beginning of each test shall not be less than the rated load of the tire. 5.3.1.2 Test inflation internal pressure
The test inflation internal pressure shall be the inflation internal pressure when the load radius of the tire on the flywheel of the testing machine is equal to the load radius specified in 4.3.3 under the specified ambient temperature. The internal pressure of the test charge shall not be adjusted to compensate for an increase in the internal pressure of the charge due to an increase in temperature during the test. 5.3.1.3 Sample
shall use the same tire to complete the dynamic simulation test specified in this standard. 5.3.2 Low-speed tires
Tires with a ground speed less than or equal to 193km,h should be able to pass 200 landing tests on a dynamic simulation testing machine using test method A or test method B under the following test temperature and kinetic energy conditions . 5.3.2.1 Test temperature
should be used for at least 90% of the test times. The gas temperature in the tire cavity or the temperature of the hottest point of the tire carcass at the beginning of the test should not be lower than 41C, and the remaining 10% of the test times should be tested. At the beginning, the temperature of the gas in the tire cavity or the hottest point of the tire body should not be lower than 27C. The tire is allowed to roll on the flywheel to reach the minimum test starting temperature. 5.3.2.2 Kinetic energy
The kinetic energy of the flywheel absorbed by the tire during the test should be calculated according to formula (2): KE=CWV?-5.06W
where: KE--kinetic energy J; ||tt ||C——0.013
W——The rated load of the tire, kg;
V-
193km/h.
5.3.2.3 Test method A—Variable mass flywheel (2)
Divide the total number of landing tests into two equal groups according to the following speed range. If a certain number of flywheel pieces cannot be used to obtain the calculated kinetic energy or the required flywheel width, a flywheel with a larger number of pieces should be used and the dynamic test speed should be adjusted to obtain the required kinetic energy. 5.3.2.3.1 Low-speed landing
In the first group of 100 landing tests, the maximum landing speed of the tire is 145km/h, and the minimum departure speed is 0. The landing speed of the tire should be adjusted so that the kinetic energy absorbed by the tire during landing is equal to 56% of the kinetic energy calculated according to equation (4) in 5.3.2.2. If the adjusted landing speed is less than 129km/h, the following processing should be done: use the flywheel kinetic energy at a speed of 103km/h plus 28% of the kinetic energy calculated according to 5.3.2.2 equation (4) to determine the landing speed of the tire; use The land-leaving speed is determined by subtracting 28% of the kinetic energy calculated according to 5.3.2.2 Equation (4) from the flywheel kinetic energy at a speed of 103km/h. 5.3.2.3.2 High-speed landing
For the second group of 100 landing tests, the minimum landing speed is 193km/h and the normal departure speed is 145km/h. If necessary, the departure speed should be adjusted so that the kinetic energy absorbed by the tires during landing is equal to 44% of the kinetic energy calculated according to equation (4) in 5.3.2.2. 5.3.2.4 Test method B--Fixed mass flywheel wWGB9745--1995
Divide the total number of landing tests into two equal groups according to the following speed range. Each landing test shall be at the calculated time T. Completed within the tire so that the tire absorbs the kinetic energy determined according to equation (2) in 5.3.2.2. Time T. Calculate according to formula (3): KEc
TeKEwn-KEwKEw-Ew
[Tiu,-TiuTw-Tw
For the test where the speed attenuates from 145km/h to 0, formula (3 ) can be simplified into formula (4): KEc
Te=KEwau]
KEwn
[TUL‖
LTwL
where: Te|| tt||KEc
KEw
Tt
Ta
(UL)-
(LL)-
5.3.2.4.1
The time required for the tire to absorb the specified kinetic energy, s, the kinetic energy that the tire should absorb for each landing test, small; the kinetic energy of the flywheel at a given speed, J; the decay time of the flywheel speed under the rated load of the tire , S; the decay time of flywheel speed when there is no tire load, s; ??the subscript of the upper speed limit;
the subscript of the lower speed limit.
Low speed landing
.(3)
(4)
In the first group of 100 landing tests, the tire should be at a speed of not less than 145km/h on the flywheel circumference When landing, within time Te, the flywheel speed decelerates from 145km/h to 0 at a constant speed.
5.3.2.4.2 High-speed landing
For the second group of 100 landings, the tires should land when the flywheel peripheral speed is not less than 193km/h. h decelerate to 145km/h.
5.3.3 High-speed tires
In addition to the provisions in the replacement test, tires with a ground speed greater than 193km/h shall undergo dynamic simulation tests in accordance with the provisions of 5.3.3.3. The test curve as the basis of the test shall be determined according to the provisions of 5.3.3.3.2. The tire load at the beginning of each test shall be equal to the tire's rated load. For tires with a ground speed greater than 193km/h and less than or equal to 257km/h, the landing test in the test can be replaced by 5.3.3.4. 5.3.3.1 Test temperature
At least 90% of the test times specified in 5.3.3.3.4. When the test starts, the temperature of the gas in the tire cavity or the temperature of the hottest point of the tire carcass should not be lower than 49°C; overload Test (5.3.3.3.3) and at least 90% of the number of tests specified in 5.3.3.3.2 and 5.3.3.4.At the beginning of the test, the temperature of the gas in the tire cavity or the temperature of the hottest point of the tire body should not be lower than 41C. For the remaining 10% of the test times in each group of tests, at the beginning of the test, the temperature of the gas in the tire cavity or the temperature of the hottest point of the carcass should not be lower than 27C. Allow the tire to roll on the flywheel to obtain the minimum test starting temperature.
5.3.3.2 Test speed
The dynamic simulation test speed corresponding to the maximum ground speed of the aircraft is shown in Table 1: Large
GB9745—1995
The dynamic simulation test speed corresponding to the ground speed is the maximum ground speed of the aircraft, km/h
at
193
257
306
338||tt ||362
378
less than or equal to
257
306
338
362
378||tt ||394
Tire rated speed
km/h
257
306
338
362
378| |tt||394
For tires with a ground speed greater than 394km/h, the appropriate rated speed value should be marked according to the latest load of the tire.
Speed
Minimum dynamic test speed at S2 point
km/h
257
306
338
362 | |tt | Overload takeoff and 10 taxiing tests, the test sequence can be determined arbitrarily. 5.3.3.3.1 Symbol definition
The specific values ??of the following symbols should be determined based on the load-speed-time data of the corresponding aircraft.
Lo
Tire load at the beginning of takeoff (should not be less than rated load), kg; L. Tire load at inflection point.kg
L2
RD-
S.
Tire zero load (land load);
Rolling distance, m;
Zero tire speed;
Tire speed at the turning point, km/h;|| tt||S,
S. Tire speed when leaving land (should not be lower than rated speed), km/h; T. —Start taking off;
T
T
The rolling time to the turning point, s;
The rolling time to the time of leaving the land, s.
5.3.3.3.2 Take-off test
The load, speed and distance relationship curve of the tire during the take-off test shall comply with the provisions of Figure 1 or Figure 2. The test conditions specified in Figure 1 are applicable to any aviation tire. If Figure 2 is selected as the test basis, the test load, speed and distance should be selected according to the most demanding take-off conditions of the tire.
5.3.3. 3.3
Overload take-off test
The overload take-off test is the same as the take-off test specified in 5.3.3.3.2, except that the test load is increased to 1.50 times. 5.3.3.3.4 Slide test
The tire shall pass 10 slide tests on the dynamic simulation testing machine according to the test conditions specified in Table 2. Table 2 Slide test conditions
Number of tests
8
2
Minimum tire load
kg
Rated load
1.2 times rated load
Minimum speed
km/h
64
Minimum rolling distance
m
10668
5.3.3.4
Replacement test
For tires with a rated speed of 257km/h, the simulated landing test can be used to replace the take-off test specified in 5.3.3.3.2 and 5.3.3.3.3 GB9745-1995|| tt||verification. The tire shall pass 100 tests specified in 5.3.3.4.1 under rated load, and then pass 100 tests specified in 5.3.3.4.2 under rated load.
Low-speed landing test
5. 3.3.4.1
For the first group of 100 landing tests, the test procedure shall comply with the low-speed landing test method specified in 5.3.2.3 or 5.3.2.4. 5.3.3.4.2 High-speed landing test
The second set of 100 landing tests, except that the landing speed of the tire under rated load is 257km/h, the test procedure should comply with the provisions of 5.3.2.3 or 5.3.2.4 Low speed landing test method. If necessary, the tire's landing speed should be adjusted so that the kinetic energy absorbed by the tire during landing is equal to 44% of the kinetic energy calculated according to equation (4) in 5.3.2.2. 5.4 The overpressure performance of tires is tested according to GB/T11191. 5.5 The static load performance of the tire is tested according to GB/T11192. The air tightness performance of the tubeless tire is tested according to GB/T11194. 5.6
5.7 The internal defects of the tire are tested according to GB/T13653 or GB/T13654. 5.8 The static balance difference of the tire is tested according to GB/T13655. The physical properties of the tire are tested according to GB/T13656. Among them, the cutting knife can be separately specified as needed. 5.9
6 Inspection Rules
6.1 Product Acceptance
The product quality inspection department of the tire manufacturer shall conduct quality inspection in accordance with the provisions of this standard. After passing the inspection, the representative of the ordering party will be responsible for acceptance.
6.2
Product batching
Tires are batched according to specifications and levels. During a continuous production cycle and under basically the same production conditions, tires of the same specification and level will be grouped into a batch of 500 pieces, and tires exceeding 500 will be grouped into separate batches. For tires with large output and stable quality, we can also make a batch of 1,000 pieces.
6.3 Inspection Categories and Inspection Items
6.3.1 Inspection Categories
Inspection is divided into two categories: factory inspection and type inspection. Factory inspection refers to various inspections that should be carried out when products are delivered, and type inspection refers to a comprehensive assessment of product quality, that is, all dimensional and performance requirements specified in this standard are inspected. When one of the following situations occurs, type inspection should be carried out when new products are put into production or old products are transferred to factory production; after formal production, if there are major changes in structure, main materials, and processes: the factory inspection results are the same as the last type inspection When the results are significantly different: when the national quality supervision agency requests type inspection. 6.3.2 Inspection items
6.3.2.1 Factory inspection items
6.3.2.1.1 All inspection items
a) Finished product surface quality:
b) Static balance difference degree;
6.3.2.1.2 Sampling inspection items
a)
Maximum inflation size (excluding tire shoulder size): tubeless tire air tightness performance;
b)
Overpressure performance:
e
d) Internal defects;
e) Weight;
f) Physical properties. | |tt | ) Dynamic performance;
b) Static load performance;
c) Temperature performance;
d) Shoulder size.
6.4 Sampling plan
Select samples according to random sampling method to ensure the consistency between the sample and the whole. Products with surface defects that do not affect the test results are allowed to participate in sampling, but cannot be designated as test samples. The number of samples for each inspection item is specified as follows: a) Samples for internal defect inspection in the sampling inspection items of factory inspection are selected from 5% to 10% of each batch of products; b) Samples of other sampling inspection items in the factory inspection items One tire is selected from each batch for testing; two tires are selected for each type inspection item, one for dynamic simulation testing, and the other for other item inspections; c)
d) When the number of samples is insufficient, During each inspection, more samples can be added according to actual needs. 6.5 Judgment Rules
a) When the surface quality of the finished product fails the inspection according to GB/T13652, it shall be removed from the batch of products. b) If the static balance difference fails to pass the inspection according to the provisions of this standard, it shall be patched to make it meet the specified requirements; the maximum weight of the tire after patching shall not exceed the design requirements.
c) Sampling inspection items, if the inspection results comply with the provisions of this standard, the batch shall be judged as qualified products. If the products still do not meet the requirements of this standard after re-inspection, the batch of products shall be judged as unqualified products. d) In the samples for internal defect inspection, any steel wire breakage, carcass delamination, carcass cord breakage, cord failure, etc. are found. If the tire has serious bending or other defects, the tire shall be deemed to be unqualified. Then take double samples for inspection. If any defective products are still found, all inspections should be carried out. e) When the weight of the sample exceeds the design requirements, all products in the batch should be weighed. Any overweight products will be deemed unqualified. 6.6 Re-inspection rules
When unqualified products are found during sampling inspection, double samples are allowed to be taken for re-inspection. The retest rules are as follows: a) For items such as maximum inflation size, tubeless tire air tightness, burst pressure, physical properties, etc., two more samples can be randomly selected from the same batch of products for retest. When the test results of both samples are qualified, the batch of products can be judged as qualified products, otherwise they should be judged as unqualified products; b) The four main indicators of physical properties are: tensile strength, elongation at break When any one of the water-lasting deformation at break and 300% modulus stress fails to meet the specified requirements, the above four items should be re-inspected at the same time. If all four re-inspection results are qualified, the batch of products shall be judged as qualified products, otherwise they shall be deemed as unqualified products;
c) The re-inspection rules for internal defects and weight shall be implemented in accordance with d and e in 6.5 of this standard. 6.7 Acceptance documents
The products submitted by the tire manufacturer to the ordering party's representative for acceptance should have an acceptance certificate and include the following documents: a) Product acceptance card:
b) Maximum inflation size measurement report, overpressure Performance test report, tubeless tire air tightness performance test report, physical performance test report (including tire weight), static balance test report, X-ray or holographic inspection report, product serial number and product qualification certificate. 7 Marks, Packaging, Use and Storage
7.1 Marks
The sidewall of the tire should have the following marks, of which items a) to j) are permanent marks; a) specifications; ||tt| |
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