QC/T 242-2024 Static unbalance requirements and test methods of vehicle wheels
1 Scope
This document specifies the static unbalance requirements and test methods of wheels.
This document is applicable to the determination for amount of static unbalance of vehicle wheels.
2 Normative references
The following documents contain requirements which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 2933 Wheels and rims for pneumatic tyres - Vocabulary, designation and marking
GB/T 6444 Mechanical vibration - Balancing - Vocabulary
GB/T 9239.21 Mechanical vibration - Rotor balancing - Part 21: Description and evaluation of balancing machines
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 2933 and GB/T 6444 and the following apply.
3.1
mass eccentricity
distance from the center of mass of the wheel to the centerline of the wheel
3.2
amount of static unbalance
U
product of the mass of the wheel and the mass eccentricity (3.1)
Note 1: Unit: g·cm.
Note 2: As shown in Figure 1, it is calculated using Equation (1):
U=M×e (1)
Where,
M——the mass of the wheel, g;
e——the mass eccentricity, cm.
Figure 1 Schematic diagram for amount of static unbalance
3.3
correction radius
distance from the center of mass of the wheel counterweight to the centerline of the wheel
3.4
static unbalance mass
m
quotient of the amount of static unbalance (3.2) divided by the correction radius (3.3)
Note 1: Unit: g.
Note 2: As shown in Figure 2, it is calculated using Equation (2):
m=U/r (2)
Where,
U——the amount of static unbalance, g·cm;
r——the correction radius, cm.
Figure 2 Schematic diagram for static unbalance mass
3.5
angle of static unbalance
circumferential angle between the center of static unbalance mass (3.4) and the designated reference point
4 Samples to be tested
4.1 The samples to be tested shall be new wheels that have not been used.
4.2 The wheel samples with two-piece rim or with multi-piece rim may not be equipped with spring flange and lock ring before test.
Contents
Foreword III
1 Scope
2 Normative references
3 Terms and definitions
4 Samples to be tested
5 Test equipment
6 Static unbalance requirements
7 Test methods
