SAE J2318:2020 pdf free

SAE J2318:2020 pdf free.Air Brake Actuator Test Performance Requirements – Truck and Bus
This procedure provides test performance requirements for service, spring applied parking, and double diaphragm combination air brake actuators with respect to durability, function, and environmental performance when tested in accordance to SAE J1469.
This SAE recommended procedure provides uniform minimum requirements for air brake actuators used in air brake systems for trucks, truck-tractor, bus, and trailers.
Hold-off pressure (pressure decreasing) is typically measured at 5 mm (0.20 inch) stroke of the parking chamber from the actuator zero stroke position. A maximum target hold-off pressure of 483 kPa (70 psi) will, in most applications,ensure the brakes will not drag. This requirement may vary depending on a vehicle air brake system, which may allow a higher hold-off pressure or require a lower hold-off pressure. A low hold-off pressure is preferred to ensure brakes do not drag.
Parking force output requirements for the most common standard and long-stroke diaphragm actuated parking chambers are given in Table 2 for reference purposes only. Forces given are the minimum and maximum allowed. Parking chamber force output is measured for a complete (tandem) actuator after the power spring has been fully caged1 for 24 hours. Test procedures other than SAE J1469 may require the spring be fully caged for 56 days or some other time period. The forces given in Table 2 are only applicable to test procedure SAE J1469.
There are various levels of parking forces for the same type (size) parking chambers, only the most common forces are given in Table 2. It is therefore incumbent upon OEM vehicle manufacturers to assure each vehicle meets grade holding or draw bar holding requirements, as well as required stopping distances in accordance to FMVSS 121 for the specified parking chamber.
Data given is for the most common type (size) clamp band/sealed design service chambers and service side of tandem (combination) spring brake actuators. The forces charted are for double diaphragm actuators, as well as for rotochambers – service.
NOTE: The intent of these tables is to provide industry minimum service application forces for the purpose of engineering calculations. There may, however, be some variations to these values due to manufacturers design differences.SAE J2318 pdf free download.