GB/T 42356-2023Test methods for the rolling resistance of industrial tyres (English PDF)

1 Scope

China's national test methods for the rolling resistance of industrial tyres. Rolling resistance is well established as a measurement for car and truck tyres, where it drives fuel consumption and is regulated and labelled. Industrial tyres - the solid and cushion tyres of forklifts, and the tyres of other materials handling equipment - had no equivalent, and the case for measuring them has been made by electrification. A diesel forklift's fuel cost was a minor line; a battery forklift's rolling resistance directly determines how long it runs between charges, and therefore whether a fleet needs a spare battery per truck. Measuring it is different from the car case because these tyres are solid or nearly so, they run at low speed under high load, and much of their loss is hysteresis in a thick rubber section rather than in a flexing carcass - so the test conditions have to reflect the duty rather than being borrowed.

This document describes the test methods for rolling resistance of industrial tyres, including test equipment and accuracy, test conditions, test procedures, additional loss measurement, data processing and repeatability testing of rolling resistance testing machine. This document is applicable to the testing of rolling resistance of pneumatic and solid tyres for industrial vehicles.

2 Normative References

The contents of the following documents constitute indispensable clauses of this document through the normative references in the text. In terms of references with a specified date, only versions with a specified date are applicable to this document. In terms of references without a specified date, the latest version (including all the modifications) is applicable to this document.

GB/T 2982 Designation, Dimensions, Inflation Pressure and Load Capacity of Pneumatic Tyres for Industrial Vehicles

GB/T 6326 Tyre Terms and Definitions

GB/T 10823 Size Designation, Dimensions and Load Capacity of Solid Tyres for Pneumatic Tyres Rims

GB/T 12939 Rims Series for Industrial Vehicles

GB/T 16622 Size Designation, Dimensions and Load Capacity for Pressed-on Solid Tyres

GB/T 16623 Technical Specification of Pressed-on Solid Tyres

GB/T 29040 Test Methods of Rolling Resistance for Motor Vehicle Tyres - Single Point Test and Correlation of Measurement Results

3 Terms and Definitions

The terms and definitions defined in GB/T 6326 and GB/T 29040 are applicable to this document.

4 Measurement Methods

This document provides four measurement methods. The tester can choose to use any measurement method. No matter which method is chosen, the measurement results shall be converted into rolling resistance values between the tyre / drum contact surface. The four measurement methods are:

a) Tyre axonometric method: measure or convert into the counter-acting force on the axle of the tyre;

b) Drum shaft torque method: measure the input torque of the drum;

c) Power method: measure the energy input to the drum;

d) Deceleration method: measure the deceleration of the drum and the tyre rim assembly. NOTE 1: in the tyre axonometric method, the measured values include the bearing losses and aerodynamic losses of the tyre rim assembly, which are taken into account in further data processing. NOTE 2: in the drum shaft torque method, power method and deceleration method, the measured values also include the bearing losses and aerodynamic losses of the tyre rim assembly and the drum.

6 Test Conditions

6.1 General Rule The inflated pneumatic tyres for industrial vehicles are subjected to a rolling resistance test, and the air pressure is allowed to be raised, that is, the "capped inflation test".

6.2 Ambient Temperature The reference ambient temperature shall be 25 C. The measurement position shall be within the range of 150 mm ~ 1,000 mm from the sidewall of the tyre. When the reference temperature cannot be reached, then, it shall be corrected to the value under the reference temperature conditions in accordance with the stipulations of 9.5.

6.3 Drum Surface Temperature At the beginning of the test, the drum surface temperature shall be the same as the ambient temperature.

6.4 Test Air Pressure After the rims are installed, the pneumatic tyres for industrial vehicles shall be inflated in accordance with the requirements. The test air pressure shall be the air pressure specified in GB/T 2982 or related industry technical documents; the inflation pressure shall be closed and shall comply with the tolerance range specified in A.4.

7 Test Procedures

7.1 General Rule Each stage of the test procedures shall be carried out in accordance with the sequence provided in 7.2 ~ 7.4.

7.2 Thermal Equilibrium After the pneumatic tyres for industrial vehicles are inflated, after parking at ambient temperature for 24 h, the air pressure shall be adjusted to the test air pressure, and then, verified after adjustment for 10 min. The solid tyres for industrial vehicles shall be parked for 24 h at ambient temperature.

7.3 Heating-up Carry out heating-up driving of the test tyres in accordance with Table 1, Table 2 and the following stipulations:

a) Solid tyres for industrial vehicles: heat up for 15 min;

b) Pneumatic tyres for industrial vehicles: heat up for 3 h.

7.4 Measurement and Record The following data shall be measured and recorded during the test:

a) Test speed (Un);

b) Tyre test load (Lm) perpendicular to the drum surface;

c) Initial test air pressure;

d) Measured rolling resistance coefficient (Cr), rolling resistance coefficient percentage (dCr), and its corrected value (dCr,corrected) under the conditions of 25 C and

e) Ambient temperature (tamb);

f) Drum radius (R);

g) Tyre load perpendicular to the drum surface when the additional loss is measured by the separation method;

h) The selected test method;

Appendix A

(Normative) Test Equipment Tolerances A.1 Overview In order to obtain test results with a good reproducibility and correlate the test results among laboratories, it is necessary to specify the test equipment tolerances. The tolerances described in this Appendix are not meant to represent a complete set of technical requirements for test equipment, instead, the tolerances are used as a guide for obtaining reliable test results. A.2 Test Rims A.2.1 Width For pneumatic tyres for industrial vehicles and solid tyres for pneumatic tyre rims, the rim width shall comply with the measured rim width specified in GB/T 12939 or related industry technical documents. A.2.2 Runout The jerk value of the test rim shall comply with the following stipulations:

---maximum radial runout:

0.5 mm;

---maximum lateral runout:

0.5 mm. A.3 Positioning A.3.1 General rule The angular deviation is critical to the test results. A.3.2 Load loading The direction of tyre loading shall be kept perpendicular to the test drum surface, and shall pass through the center of the drum. The allowable deviation shall be:

---The tyre axonometric method and deceleration method: 1 mrad;