ISO-3450-1996.pdf
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1、INTERNATIONAL STANDARD IS0 3450 Third edition 1996-04-o 1 Earth-moving machinery - Braking systems of rubber-tyred machines - Systems and performance requirements and test procedures Engins de terrassemen t - Dispositifs de freinage des engins sur roues kquip V is the velocity of the machine immedia
2、tely prior to the brake control being activated, in metres per second; is the stopping distance, in metres. 3.7 burnish: Procedure to condition the frictional surfaces of the machine brake(s). 3.8 brake system pressure: Fluid pressure available to the brake control. 3.9 brake application measured at
3、 the brake. pressure: Fluid pressure 3.10 modulated braking: Capability to continuously and progressively increase and decrease the braking force by operation of the brake control. 3.11 test course: Surface upon which the test is carried out. (See 6.2.) 3.12 cold brakes: Expression designating brake
4、s where the brakes have not been actuated in the previous 1 h, except in accordance with 6.9; or the brakes have been cooled to 100 “C or less when measured on the brake disc or on the out- side of the brake drum; or in the case of totally enclosed brakes, including oil-immersed brakes, the temperat
5、ure measured on the outside of the housing closest to the brake is below 50 “C or within the manufacturers specifications. 3.13 chine maximum machine level surface speed: Ma- speed determined in accordance with IS0 6014, or equivalent. 4 Instrument accuracy The instruments used to carry out the requ
6、ired measurements shall conform to conditions of IS0 9248. 5 General requirements The following requirements for brake systems apply to all machines given in clause 1. 5.1 Required brake systems The machine shall have the following brake systems: a) a service brake system; b) a secondary brake syste
7、m; d a parking brake system. No brake system shall contain a disconnect such as a clutch or shiftable gear-box which allows the brake(s) to be disabled. A power source disconnect designed for cold weather starting which also disables a brake system shall re- quire application of the parking brake pr
8、ior to discon- nection. 2 -,-,- 0 IS0 IS0 3450: 1996(E) 5.2 Common components Brake systems may use common components. How- ever, a failure of any single component other than a tyre, or a failure of any single common component, shall not reduce the effectiveness of the machines stopping capability t
9、o less than the secondary per- formance defined in 5.4, and table 2, 3 or 4, as appli- cable, with one exception: a common control (lever, pedal, switch, etc.) may be used to actuate combined service and secondary brake systems provided that another dynamic braking capability is provided that will s
10、top the machine within 120 % of the dynamic stopping distance shown for secondary brakes in ta- ble 2, 3 or 4, as applicable. This braking capability may be applied automatically and without modulation. 5.3 Service brake system 5.3.1 All machines shall meet the service brake per- formance requiremen
11、ts of 7.5, 7.6 or 7.7 as appli- cable. If other systems are provided with power from the service brake system, any failure in these systems shall be considered to be the same as a failure in the service brake system. 5.3.2 All machines shall have brakes of equal nom- inal capacity rating applicable
12、to each wheel of at least one axle. Machines with semi-trailed units shall have brakes applicable to at least one axle of the towing machine and one axle of the semi-trailed units. 5.3.3 The service brake system shall be modulated as defined in 3.10. 5.4 Secondary brake system All machines shall mee
13、t the secondary brake per- formance requirements of 7.6 or 7.7, as applicable. The secondary brake system shall be modulated as defined in 3.10. 5.5 Parking brake system A parking brake disconnect (release) designed to al- low movement of disabled machines shall be located outside the operators stat
14、ion unless it can be reap- plied immediately. All machines shall meet the parking brake require- ments of 7.5. After being applied, this system shall not depend on an exhaustible energy source. The parking brake sys- tem may systems use comma provided the in components with other bra requirements of
15、 7.5 are met. ke 5.6 Warning device for stored energy sources If stored energy is used for the service brake system, that system shall be equipped with a warning device which is activated before the system energy drops below 50 % of the maximum operating energy level specified by the manufacturer or
16、 the level required to meet the secondary brake performance requirements, whichever level is higher. The device shall readily attract the operators attention by providing a continuous visible and/or audible warning. Gauges indicating pressure or vacuum do not meet this requirement. 6 Test conditions
17、 61 while Manufacture carrying out rs Pe preca f-forma utions nce te shall be observed sts. 6.2 The test course shall consist of a hard, dry sur- face with a well-compacted base. Ground moisture may be present to the extent that it does not ad- versely affect the braking test. The test course shall
18、not have a slope of more than 3 % at right angles to the direction of travel. Slope in the direction of travel shall be as specified for the test being carried out. The approach to the test course shall be of sufficient length, smoothness and uniformity of slope to ensure the required machine speed
19、is reached before the brakes are actuated. 6.3 The machine mass and axle load distribution shall be as defined in 6.3.1 or 6.3.2, as applicable. 6.3.1 The test mass of all machines except dumpers and tractor-scrapers shall be as stated in 3.4 without a payload and at the manufacturers specified axle
20、 load distribution. 6.3.2 The test mass of dumpers and tractor-scrapers shall be as stated in 3.4 and include a payload. The machine test mass shall be equal to the manufac- turers specifications for gross mass (the sum of the machine mass and payload) and axle load distribution. 6.4 All parameters
21、relating to braking systems shall be within the machine manufacturers specifications, i.e. tyre size and pressure, brake adjustment, warning 3 -,-,- IS0 3450:1996(E) 0 IS0 actuation point, etc. All brake system pressures shall be within the machine manufacturers specification range. No manual adjust
22、ment(s) shall be made to the braking system during any single performance test. 6.5 When the machine transmission provides a selection of gear ratios, the stopping tests shall be conducted with the transmission in the gear corre- sponding to the test speed specified. The power train may be disengage
23、d prior to completing the stop. 6.6 Retarders shall not be used during the service brake performance test, but they are allowed to be used during the secondary brake performance test. 6.7 Machines with operator-selectable multiple drive axles shall be brake-performance-tested with the non-braked sel
24、ectable axle(s) disengaged. 6.8 Equipment (blades, buckets, dozers, etc.) shall be carried in the transport position recommended by the manufacturer. 6.9 Burnishing or conditioning of brakes before testing is permissible. The burnishing procedure shall be indicated in the operators and/or maintenanc
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