Draft Indian Standard PERFORMANCE REQUIREMENTS AND METHODS OF TEST FOR WHEELS FOR PASSENGER CARS/MINI GOODS CARRIERS (First Revision of IS 9436)

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1 Draft for comments only Draft Indian Standard PERFORMANCE REQUIREMENTS AND METHODS OF TEST FOR WHEELS FOR PASSENGER CARS/MINI GOODS CARRIERS (First Revision of IS 9436) Not to be reproduced or used as a standard without the permission of BIS Last date for comments: 29 February 2012 FOREWORD (Formal clauses will be added later) 1 SCOPE This standard specifies laboratory test methods and performance requirements for evaluating certain essential strength characteristics of wheels used in passenger cars and mini goods carriers (wheels of four wheeler vehicles) as defined in IS : 2011 Automotive Vehicles Types Terminology. 1.1 Test Termination for the tests on wheels has also been specified. 2 General Only fully processed new wheels which are representative of wheels intended for the vehicle shall be used for the tests. No wheels shall be used for more than one test. 3 Tests Following two tests are covered: a) Dynamic cornering fatigue test; and b) Dynamic radial fatigue test. 3.1 Dynamic Cornering Fatigue Test Equipment The test machine shall have a driven rotatable device whereby either the wheel rotates under the influence of a stationary bending moment or the wheel is stationary and is subjected to a rotating bending moment. For testing fixture details see Fig.1 1

2 Fig. 1 Example of Dynamic Cornering Fatigue Test Fixture Procedure Preparation The rim flange of the wheel shall be clamped securely to the test fixture. The face by which the wheel center is supported on the testing machine shall have the same fixation characteristics as the face of the hub used on the vehicle. The load arm and adapter assembly shall be attached to the mounting surface of the wheel using non-lubricated studs, lubricated studs and nuts (or bolts), in good condition, representative of those used on the vehicle. These wheel nuts (or bolts) shall be tightened at the beginning of the test to the vehicle/wheel manufacturer s specified torque values. Wheel bolts or nuts may be re-torqued during the test. Tightening torque shall not fall below 50 percent of its initial value when the minimum load cycle number has been attained. The bending movement shall be maintained within ± 2.5 percent. The mating surfaces of the test adaptor and wheel shall be free of excessive scoring and deformation, and excessive build-up of paint, dirt or foreign matter. 2

3 Bending moment To impart a bending moment to the wheel, a force may be applied either perpendicular or parallel to the plane of the mounting surface of the wheel at a specified distance (moment arm). (See Fig.1) Bending Moment Determination The bending moment M (force x moment arm) in Newton meters, is determined from the formula: M = (R.µ + d) F v x S Where, R = static loaded radius in meters of the largest tyre to be used on the wheel as specified by the vehicle manufacturer. µ = coefficient of friction developed between tyre and road; d = inset or outset of the wheel in meters; F v = is the maximum vertical static load on the wheel or the wheel load rating in N, as specified by the vehicle or wheel manufacturer; S = accelerated test factor. NOTE For values of µ and S, see Annex A (Table 2) Test Termination a) Inability of the wheel to sustain load; b) A fatigue crack penetrating through a section of the wheel; and c) The wheel shall withstand a minimum load cycles without failure as mentioned in Annex - A (Table 2). 3.2 Dynamic Radial Fatigue Test Equipment The test machine shall be equipped with a means of imparting a constant radial load as the wheel rotates. The suggested equipment incorporates a driven rotatable drum set which presents a smooth surface wider than the loaded test tyre section width. The preferred diameter of the drum is 1700mm (nominal). The test wheel (single application) and tyre fixture shall provide loading normal to the drum external surface and in line radially with the center of the test wheel and the drum. The axes of the drum and test wheel shall be parallel (see Fig. 2). 3

4 Fig. 2 Example of Dynamic Radial Fatigue Test Fixture The mating surfaces of the test adaptor and wheel shall be free of excessive scoring and deformation, and excessive build-up of paint, dirt or foreign matter Procedure Tyres selected for this wheel test shall meet the load rating, Fv, of the wheel or be representative of the maximum load capacity size and the type specified by the vehicle or wheel manufacturer, whichever is greater. The test adaptor shall be representative of production hubs using studs or bolts and nuts which are in good condition, lubricated or non-lubricated in accordance with the intended vehicle application(as specified by the vehicle manufacturer), and are representative of those specified for the wheel. The cold inflation pressure of the test tyre shall be in accordance with the values given in Table 1. 1) 100kPa = 1 bar. Table 1 Test Inflation Pressures Service pressure kpa 1) Test pressure kpa up to to to

5 There will be an increase in pressure during the test. This increase is normal and no adjustment is necessary. The loading system shall maintain the specified load within ± 2.5% of the calculated values Radial Load Determination Determination the radial load Fr in newtons, from the formula: Where, F r = F v K F v = the maximum vertical static load on the wheel or the wheel load rating, in newtons, as specified by the vehicle or wheel manufacturer. K = the accelerated test factor, [see Annex A (Table 3)] Test Termination:- a) Inability of wheel to sustain load b) A fatigue crack penetrating through a section of the wheel. c) The wheel shall withstand a minimum test cycles without failure as mentioned in Annex A (Table 3). 5

6 ANNEX A A-1 TEST FACTORS To permit a uniform application of the test methods specified, the test factors given in the following table should be used when conducting the tests used in passenger cars and mini goods carriers. (Three wheelers and four wheelers wheels) Table 2 Test Factors and Minimum Cycle Requirements for Wheels in Normal Highway Service Dynamic Cornering Fatigue Test Ferrous All ,000 S µ * Aluminum All ,000 * For ABS brakes, use µ = 0.8 Table 3 Test Factors and Minimum Cycle Requirements for Wheels in Normal Highway Service Dynamic Radial Fatigue Test K Ferrous All ,000 Aluminum All ,000 Table 4 Test Factors and Minimum Cycle Requirements for Temporary Use Spare Wheels Dynamic Cornering Fatigue Test Ferrous All ,000 Aluminum All ,000 * For ABS brakes, use µ = 0.8 S µ * Table 5 Test Factors and Minimum Cycle Requirements for Temporary use Spare Wheels Dynamic Radial Fatigue Test K Ferrous All ,000 Aluminum All ,000 6