Tyres and wheels

BS AU 50-1.0.1:1999 pdf free.Tyres and wheels一 Part 1: Tyres- Section 0: General – Subsection 1: Method of test for measuring tyre uniformity.
4.1.1.3 Rotational torque should preferably be applied from the tyre axis; alternatively it may be from the drum axis.
There should he provisions for both clockwise and counter clockwise directions of rotation.
4.1.1.4 The equipment shall be capable of rotating tyres at a rotational frequency of at least 10 r/min and not higher than 250 r/min during the measuring operations.
4.1.2 Structural resonant frequencies The supporting structure and components of the machine shall be so designed that the influence of natural frequencies, within the measurement frequency range, does not alter the measured parameters more than 10 %.
4.1.3 External tqbrations
Sufficient isolation of the equipment shall he provided in order to minimise the influence of the environment on measured parameters.
4.2 Test drum
4.2.1 The preferred outer diameters of the drum are:
854 mm for type A, and 1600 mm for type B.
NOTE The actual specified outer diameter can be comprised between:
830 mm and 1 000 mm (reference being 854 turn) for type A.
and 1520 mm and 1 710 mm (reference being 1 600 mm) for
type B.
If other drum diameters are used, their correlation with the preferred diameters is to be checked.
4.2.2 The run-out of the outer surface of the drum. as measured at a reference hand, shall be less than 0,05 mm when using type A test drum, and 0,1 mm when using type B test drum.
4.2.3 The unbalance of the test drum, which is critical in case forces are measured at the drum axis,shall remain less than the values given in Table 1.
4.2.4 The width of the drum surface shall be greater than the footprint of the tyre tested.
4.2.5 The drum shall be provided with a high-friction coarse-textured outer surface in order to prevent lateral forces generated during the measurement from causing the tyre to skid on the drum.
4.3 Test rim
4.3.1 The rim width shall he equal to that of one of the rims permitted by ISO 4000-1, Iso 4000-2, Iso 4209-1, Iso 4209-2, ISO 4249-1, ISO 4249-2, ISO 4249.3, 150 5751-1, Iso 5751-2. ISO 6054-1 and ISO 6054-2, and preferably equal to the measuring rim width.
4.3.2 The specified diameter and the inner contour of the test rim for the measurement of forces and/or geometry shall generally conform to the standard diameter and contour, but some modifications of the contour may be required to facilitate mounting, dismounting and proper seating of the tyre beads for repeatable data.
Wheels having special contours for bead retention (e.g. humps, etc.) shall be avoided.
4.3.3 The rims shall be sufficiently rigid to ensure that deflection in any direction at the bead seat, when operating under load, is less than 0,125 mm.
4.3.4 The rims shall have a peak-to-peak run-out at the bead seats, in both radial (bead seat portion) and axial (inner surface of flange) directions, when installed with normal piloting on the apparatus, less than the values given in Table 2.
4.3.5 The difference in diameter on the two bead seats of the test rim shall not exceed the values given in Table 3.
4.3.6 The bead seats shall be turned and polished;the two surfaces shall be symmetrical with respect to the equatorial plane of the wheel within the values given in Table 4.
4.3.7 The unbalance of the test rim, which is critical in case forces are measured at the rim axis, shall remain below the values given in Table 5.
4.4 Measuring system
4.4.1 A system of appropriate design, which includes transducers for the development of output signals, is required to isolate and detect the components of the various uniformity characteristics of tyres.
4.4.2 The transducers may be placed either between the structure supporting the tyre and the tyre (on the test rim axis) or between the structure supporting the drum and the drum (on the drum axis).
4.4.3 A matching calibration system is required for calibration of force and geometry measuring systems.
4.4.4 The measuring system may contain a position marker to indicate the angular orientation of the tyre relative to the force signals that it produces.
4.4.5 The measuring system shall be capable of measuring, in the Y and Z main directions, the force variation ranges given in Table 6.
4.5 Tyre inflation and deflation
The equipment may include means for rapid inflation and deflation of the tyre and for control of the inflation pressure during the rotation of theequipment.
4.6 Optional instrumentation Optional instrumentation may include equipment for
一 indicating peak-to-peak values of the components of force variations,
— measuring the amplitude and phase of the first
ten harmonics of the components of force
variations,
— tyre inflation pressure monitoring and control.
4.7 Ambient conditions
Temperature, pressure and humidity shall be in accordance with category B2 of TEC 60654-1. Acceleration of gravity shall be known with the required accuracy in case the calibration process of the apparatus requires weights.
5 Testing
NOTE The following operations are not intendtd to be an operational guide. All operations are not compulsory, and their order may be changed.
5.1 Preparation of the tyre for measurement
5.1.1 Room temperature shall be controlled between 5 °C and 40 °C. If the tyre temperature is not within the 5 °C to 40 °C range, leave the tyre in the ambient until its temperature falls between the above values.
5.1.2 Mount the tyre on the test rim (preferably having the same width as the measuring rim standardized for the tyre size designation) and inflate it to the pressure specified for the test.
5.1.3 Suitable mounting methods shall be applied in order to ensure proper bead seating. Such methods may require that a suitable lubricant be applied onto the tyre, or onto the rim or both, prior to assembling the tyre and the rim.
5.1.4 Care should be taken that both the tyre and the drum are free of surface contamination such as oil and dirt.
5.1.5 If needed, a suitable warm-up procedure shall be followed to ensure that local distortions in the structure of the tyre due to packaging and shipping are reduced to an acceptable level.
5.2 Measurement of forces
5.2.1 The apparatus shall be equipped with an appropriate test drum, depending on the type of tyre to be measured, in accordance with Table 7.
5.2.2 Prepare and mount the tyre on the test rim.
5.2.3 Inflate the tyre and adjust the inflation pressure of the tyre to the prescribed value, depending on the type of tyre, in accordance with Table 8.BS AU 50-1.0.1 pdf free download.Tyres and wheels