This standard specifies the technical requirements, test methods, inspection rules, marking, packaging, transport and storage of variable load equipment for railway freight car (hereinafter referred to as “variable load equipment”).
This standard is applicable to the variable load equipment with design speed less than or equal to 120 km/h or axle load of 25 t or less.
2 Normative References
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections), or revisions, of any of these publications do not apply to this standard. However parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies.
GB/T 1184-1996 Geometrical Tolerancing - Geometrical Tolerances for Features without Individual Tolerance Indications (eqv ISO 2768-2: 1989)
GB/T 1804-2000 General Tolerances - Tolerances for Linear and Angular Dimensions without Individual Tolerance Indications (eqv ISO 2768-1: 1989)
GB/T 6414-1999 Castings - System of Dimensional Tolerances and Machining Allowances (eqv ISO 8062:1994)
GB/T 9438-1999 Aluminum Alloy Castings
GB/T 9439-1988 Grey Iron Castings
GB/T 13819-1992 Copper Alloy Castings
GB/T 15114-1994 Aluminum Alloy Die - Castings
TB/T 66-1995 Technical Specification for Spring of Locomotive Brake
GB/T 1492-2002 The Method of Single Car for Railway Passenger Car and Wagon Brake
3 Technical Requirements
3.1 The service environment temperature of variable load equipment for use shall be -50℃~+70℃. And it shall be capable to maintain original operating performance when recovering to the normal temperature after it is defrosted at high temperature of 110℃ for 3 h in the defrost garage.
3.2 The variable load equipment shall be manufactured according to the drawings and technical documents approved through established procedures.
3.3 The variable load equipment shall adapt to constant pressure of train pipe which is 500kPa and 600kPa.
3.4 The variable load equipment shall not interfere with the unconditional mixing of vehicles.
3.5 The variable load equipment shall meet the basic requirements of general freight car's principal bogie for braking device.
3.6 The variable load equipment may obtain the load variation information of the freight car with the methods such as measuring the relative displacement between the bodywork of the freight car and the side bearer of bogie. Installation method of the weight sensing components in variable load equipment may be determined by the vehicle type and the form of bogie, but it shall not damage important components of the freight car.
3.7 The variable load equipment shall be capable to match with the primary control valve type and shall only make adjustment to the output pressure of control valve.
3.8 The variable load equipment shall adapt to multiform brake cylinders.
3.9 The variable load equipment shall be capable of stepless control of the air pressure filled in the brake cylinder within a relatively wider range along with the load variation of the freight car.
3.10 When the variable load equipment executes braking at any loading state from empty to loaded, the maximum effective pressure reduction for train pipe is 140 kPa (constant pressure of train pipe: 500 kPa) or 170 kPa (constant pressure of train pipe: 600kPa).
3.11 Pressure of the braking cylinder of empty freight car which frequently uses full braking or emergency braking shall be 140 kPa± 20 kPa at the constant pressure of 500 kPa after the variable load equipment is loaded. Pressure of braking cylinder of loaded car shall be the output pressure of the control valve.
3.12 The variable load equipment shall have an initial zooming of the pressure of braking cylinder, the value of the initial zooming shall not be less than 50Kpa, the pressure difference between the value of initial zooming and that after pressure drop shall not be greater than 20 kPa when the variable load equipment executes braking.
3.13 The variable load equipment shall adapt to the normal vibration state during train operation, and it shall minimize the effect of the freight car's vibration to itself. The vibration shall keep the pressure of braking cylinder constant or a little lower.
3.14 The performance of variable load equipment is steady through 2×104 times of braking-release test.
3.15 When the braking devices are damaged (such as the air pipeline is damaged, measuring benchmark drops off, etc.), the variable load equipment shall make the pressure of braking cylinder lower than the normal value.
3.16 The variable load equipment shall have the function of indicating present loading condition on appearance, as well as the dust-proof, coating and anti-theft functions.
3.17 The unmarked machining dimensional tolerance shall not be inferior to the accuracy of Grade m in GB/T 1804-2000. Unnoted geometrical tolerance shall not be inferior to the accuracy of Grade k in GB/T, 1184-1996.
3.18 Unmarked dimensional tolerance of castings shall not be inferior to Grade CT10 in GB/T 6414-1999.
3.19 Iron castings shall meet the requirements of GB/T 9439-1988.
3.20 Aluminum alloy castings shall meet the requirements for castings of category I in GB/T 9438-1999. Aluminum alloy die-castings shall meet the requirements of GB/T 15114-1994.
3.21 Copper alloy castings shall meet the requirements for castings of category I in GB/T 13819-1992.
3.22 Springs shall be manufactured in accordance with the accuracy not inferior to Grade II in TB/T 66-1995.
3.23 Rubber parts shall meet the relevant technical conditions and shall not contact oils such as kerosene, gasoline, engine oil and corrosive substances such as acid and alkali.
3.24 During assembling, silicone grease in appropriate amount shall be coated on each slipping surface and movable rubber sealing ring .
3.25 The surface of the variable load equipment components shall be coated with paint excluding the installation surface, motion matching surface and the possibly involved surfaces for adjustment.
