ISO 7643:1991 キャラバンとライトトレーラー—オーバーランブレーキ付きのカテゴリー01および02のトレーラー—ブレーキ制御用の線形ベンチテスト方法 | ページ 2

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75% of the member bodies casting a vote.

International Standard ISO 7643 was prepared by Technical Committee ISO/TC 22, Road vehicles, Sub-Committee SC 4, Caravans and light trailers.

This second edition cancels and replaces the first edition (ISO 7643:1983), certain values of which have been altered and references updated.

1 Scope

This International Standard specifies test methods for type approval testing of controls on trailers for overrun brakes. ¹⁾

The test method is based on the requirements of ECE Regulation No. 13 of the United Nations, Uniformprovisions concerning the approval of vehicleswith regard to braking. It is therefore recommended that reference should be made to this Regulation to assist with the use of this International Standard.

These test methods apply to the type approval of categories O₁ and O₂²⁾ trailers with inertia brakes by testing the control devices on a linear test bench.

2 Normative reference

The following standard contains provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. Members of IEC and ISO maintain registers of currently valid International Standards.

3 Symbols and definitions (see figure 1)

G'A	is the trailer total weight capable of being braked by the control device, as declared by the manufacturer;
G'A1	is the minimum total weight capable of being braked;
G'A2	is the maximum total weight capable of being braked;
S	is the travel of the control, in millimetres;
S'	is the effective travel of the control in millimetres;
S°	is the loss of travel, applicable to multi-axle trailers only, i.e. travel in millimetres of coupling head when this is actuated to move from 300 mm above to 300 mm below the horizontal, the transmission remaining stationary;
S"	is the spare travel of the master cylinder, measured in millimetres at the coupling head;
iH°	is the reduction ratio between the travel of the coupling head and the lever travel at the output side of the control device;
	is the reduction ratio measured at the mid-travel position of the control, and with the lever vertical;
ih	is the reduction ratio between the travel of the coupling head and the travel of the piston in the master cylinder (in the case of hydraulic transmission brakes);
	is the reduction ratio ih measured at the mid-travel position of the control;
FHz	is the surface area of the piston of the master cylinder (in the case of hydraulic transmission brakes);
KA	is the force threshold of the control device, i.e. the maximum thrust on the coupling head which can be supplied for a short time without placing any force on the output side of the control device;
D	is the longitudinal force occurring between the towing vehicle and towed vehicle;
D1	is the maximum force applied to the coupling head when it is being pushed at the speed specified in 7.1.2, with the transmission uncoupled;
D2	is the maximum force applied to the coupling head when it is being pulled at the speed specified in 7.2 from the position of maximum compression, with the transmission uncoupled;
ηH°	is the efficiency of the inertia control device;
P'	is the control device output force;
K	is the supplementary force of the control device, conventionally designated by the force D corresponding to the point of intersection with the axis of the abscissae of the extrapolated curve expressing P' in terms of D, measured with the device in the mid-travel position.