ISO 789-3:2015 農業用トラクター—テスト手順—パート3：回転直径とクリアランス直径 | ページ 2

Foreword

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The committee responsible for this document is ISO/TC 23, Tractors and machinery for agriculture and forestry, Subcommittee 2, Common tests.

This third edition cancels and replaces the second edition (ISO 789-3:1993), which has been technically revised.

ISO 789 consists of the following parts, under the general title Agricultural tractors — Test procedures:

• Part 1: Power tests for power take-off
• Part 2: Rear three-point linkage lifting capacity
• Part 3: Turning and clearance diameters
• Part 4: Measurement of exhaust smoke
• Part 5: Partial power PT0 – Non-mechanically transmitted power
• Part 6: Centre of gravity
• Part 7: Axle power determination
• Part 8: Engine air cleaner
• Part 9: Power tests for drawbar
• Part 11: Steering capability of wheeled tractors
• Part 12: Low temperature starting

ISO/OECD 789 consists of the following parts, under the general title Agricultural tractors – Test procedures:

• Part 10: Hydraulic power at tractor/implement interface

1 Scope

This part of ISO 789 specifies a method of determining the turning and clearance diameters of wheeled agricultural tractors.

It applies to wheeled agricultural tractors having at least two axles fitted with pneumatic tyres.

2 Terms and definitions

For the purpose of this document, the following terms and definitions apply.

2.2

track

tread

<wheeled tractor> distance at ground level between two vertical planes passing through the centreline of ground contact of the tires parallel to the median plane of the tractor with the wheels in the straight ahead position

Note 1 to entry: In the case of dual wheels, it is the distance at ground level between two planes passing through the centreline of the dual wheels.

Note 2 to entry: See Figure 1.

Figure 1 — Track (tread) of the wheeled tractor

2.3

wheelbase

horizontal distance between the two vertical planes passing through the rotational centrelines of the wheels ここで, one plane is for the front wheels and the other for the rear wheels

Note 1 to entry: In the case of a tractor equipped with a rear tandem, it is the distance between two vertical planes passing through the centres of the front wheel and the vertical plane midway between the wheel centres of the two axles of the tandem.

Note 2 to entry: See Figure 2.

Figure 2 — Wheelbase of the wheeled tractor

2.5

clearance diameter

diameter of the smallest circle which will enclose the outermost points of projection of the tractor and its equipment while executing its sharpest practicable turn

Note 1 to entry: See Figure 3.

Figure 3 — Tractor turning configurations