Commission Regulation (EU) 2017/2400Show full title

2. Definitions

For the purposes of this Annex the following definitions shall apply:

(1)

‘Single reduction axle (SR)’ means a driven axle with only one gear reduction, typically a bevel gear set with or without hypoid offset.

(2)

‘Single portal axle (SP)’ means an axle, that has typically a vertical offset between the rotating axis of the crown gear and the rotating axis of the wheel due to the demand of a higher ground clearance or a lowered floor to allow a low floor concept for inner city buses. Typically, the first reduction is a bevel gear set, the second one a spur gear set with vertical offset close to the wheels.

(3)

‘Hub reduction axle (HR)’ means a driven axle with two gear reductions. The first is typically a bevel gear set with or without hypoid offset. The other is a planetary gear set, what is typically placed in the area of the wheel hubs.

(4)

‘Single reduction tandem axle (SRT)’ means a driven axle that is basically similar to a single driven axle, but has also the purpose to transfer torque from the input flange over an output flange to a further axle. The torque can be transferred with a spur gear set close at the input flange to generate a vertical offset for the output flange. Another possibility is to use a second pinion at the bevel gear set, what takes off torque at the crown wheel.

(5)

‘Hub reduction tandem axle (HRT)’ means a hub reduction axle, what has the possibility to transfer torque to the rear as described under single reduction tandem axle (SRT).

(6)

‘Axle housing’ means the housing parts that are needed for structural capability as well as for carrying the driveline parts, bearings and sealings of the axle.

(7)

‘Pinion’ means a part of a bevel gear set which usually consists of two gears. The pinion is the driving gear which is connected with the input flange. In case of a SRT / HRT, a second pinion can be installed to take off torque from the crown wheel.

(8)

‘Crown wheel’ means a part of a bevel gear set which usually consists of two gears. The crown wheel is the driven gear and is connected with the differential cage.

(9)

‘Hub reduction’ means the planetary gear set that is installed commonly outside the planetary bearing at hub reduction axles. The gear set consists of three different gears. The sun, the planetary gears and the ring gear. The sun is in the centre, the planetary gears are rotating around the sun and are mounted to the planetary carrier that is fixed to the hub. Typically, the number of planetary gears is between three and five. The ring gear is not rotating and fixed to the axle beam.

(10)

‘Planetary gear wheels’ means the gears that rotate around the sun within the ring gear of a planetary gear set. They are assembled with bearings on a planetary carrier, what is joined to a hub.

(11)

‘Oil type viscosity grade’ means a viscosity grade as defined by SAE J306.

(12)

‘Factory fill oil’ means the oil type viscosity grade that is used for the oil fill in the factory and which is intended to stay in the axle for the first service interval.

(13)

‘Axle line’ means a group of axles that share the same basic axle-function as defined in the family concept.

(14)

‘Axle family’ means a manufacturer's grouping of axles which through their design, as defined in Appendix 4 of this Annex, have similar design characteristics and CO₂ and fuel consumption properties.

(15)

‘Drag torque’ means the required torque to overcome the inner friction of an axle when the wheel ends are rotating freely with 0 Nm output torque.

(16)

‘Mirror inverted axle casing’ means the axle casing is mirrored regarding to the vertical plane.

(17)

‘Axle input’ means the side of the axle on which the torque is delivered to the axle.

(18)

‘Axle output’ means the side(s) of the axle where the torque is delivered to the wheels.