GB/T 12540-2024 Minimum turning circle diameter, turning clearance circle and swing-out value test method for motor vehicles and combination of vehicles
1 Scope
This document specifies the test conditions and test methods for measuring the minimum turning circle diameter, turning clearance circle, and swing-out value of motor vehicles and combination of vehicles.
This document is applicable to motor vehicles and combination of vehicles.
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 3730.1 Terms and definitions of motor vehicles, trailers and combination vehicle - Part 1: Types
GB/T 12534 Motor vehicles - General rules of road test method
GB/T 15089 Classification of power-driven vehicles and trailers
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 3730.1 and GB/T 15089 as well as the following apply.
3.1
minimum turning circle diameter
diameter of the outermost track circle on a flat ground formed by the tread contact center of the outer steered wheel on each steering axle when the steering wheel of a motor vehicle or combination of vehicles is deflected to the limit position
Note 1: For a combination of vehicles, it refers to the maximum position where the steering wheel is deflected to the point where the wheels on the last axle of the trailer do not reversely rotate and the combination of vehicles is free of motion interference.
Note 2: See Figures 1 and 2 for the schematic diagram of the minimum turning circle diameter (d).
Figure 1 Schematic diagram for minimum turning circle diameter of motor vehicle
Figure 2 Schematic diagram for minimum turning circle diameter of combination of vehicles
3.2
turning clearance circle
circular path formed by the following two circles when a motor vehicle or combination of vehicles is turning:
a) the outer circle of turning clearance circle (diameter: d1): the smallest outer circle that encloses the projections of all points of the motor vehicle or combination of vehicles on flat ground;
b) the inner circle of turning clearance circle (diameter: d2): the largest inner circle outside which the projections of all points on the motor vehicle or combination of vehicles fall on flat ground.
Note 1: Unless otherwise specified, descriptions of all points, furthest points, outermost points, and nearest points on the vehicles in this document do not include protruding parts of devices not within the vehicle length and width measurement range and special devices with operational functions, as specified in GB 1589.
Note 2: The schematic diagram of the turning clearance circle is shown in Figure 3.
Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 Test conditions 4.1 Test site and meteorological conditions 4.2 Vehicle conditions 4.3 Measurement parameters, units, and accuracy 5 Test methods 5.1 Minimum turning circle diameter of motor vehicles 5.2 Minimum turning circle diameter of combination of vehicles 5.3 Turning clearance circle 5.4 Measurement of swing-out value Annex A (Informative) Vehicle parameter table and test record forms Bibliography
