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Your Position: Home - Transportation - Introduction of Semi Trailer Axles

Introduction of Semi Trailer Axles

A trailer axle is a device that supports all or part of the vertical load of the trailer while moving (wheel rotation) and bears various external forces in other directions to ensure the normal driving of the trailer.

A axle is one of the important parts of a trailer, It is mainly introduced from the following aspects:

1. Technical standards of axles

(1) The technical standard of axles assembly shall comply with China transportation industry standard JT / T475-2020.

(2) The axle welding standard shall comply with the China machinery industry standard JB / T5000.3-2018.

2. The composition of a trailer axle

A trailer axle is mainly composed of the following four assemblies: a axle body assembly, a camshaft assembly, a braking assembly and a wheel end assembly.


(1) Axle body assembly

It mainly includes: an axle tube, brake base plates, air chamber supports and camshaft supports, etc.

(2) Camshaft assembly

It mainly includes: camshafts, slack adjusters and a camshaft repair kit, etc.

(3) Brake assembly

It mainly includes: brake shoes, brake linings, a brake shoe accessories package, etc.

(4) Wheel end assembly

It mainly includes: hubs, brake drums, oil seals, bearings, axle nuts, and hub covers, etc.

3. Classification of axles

According to the structures of the axle, it is usually divided into the following four types:

(1) Inboard brake drum axle series:

 The flange surface of the axle brake drum is located on the inner side of the hub flange surface. For the inboard axles, when maintaining and replacing the parts of the braking system, it is necessary to screw the cover and remove the bearing locknut, so that the tires, wheel hubs, brake drums and bearings can be removed together for maintenance and replacement.

(2) Outboard brake drum axle series:

 The flange surface of the axle brake drum is located outside the flange surface of the hub. For the outboard axles, when maintaining and replacing brake system parts, it is only necessary to unscrew all wheel nuts and remove tires and brake drums.

(2) Spoke wheel hub series axle

The axle replaces the common wheel hubs with five spoke wheel hubs, six spoke wheel hubs, eight spoke wheel hubs and ten spoke wheel hubs, and matched with demountable wheel rims and spacers.

(3) Disc brake series axle

Compared with the drum axle, the overall structure of the axle is simpler, the braking friction surface is directly exposed to the air, the heat dissipation is better, and the phenomenon of heat recession is effectively avoided. The brake discs bear compressive stress on both sides, and have better crack resistance under continuous braking. The braking force of the left and right wheels is more average, and the response speed of the braking system is faster, which improves the safety of the vehicle.

4. Selection of axles

The following aspects need to be considered when selecting a axle:

(1) Axle styles

Trailer axles have usually two styles: American axles and European axles.

(2) Rated axle load

The rated axle load of the trailer axle is usually 8 tons, 10 tons, 11.5 tons, 12 tons, 13 tons, 14 tons, 16 tons, 18 tons and 20 tons.

(3) Specifications of axle tube

There are usually two types of trailer axle tubes: square tubes and round tubes: square tubes usually have 150x150mm, 127x127mm and 120x120mm, and round tubes usually have Φ127mm and Φ146mm.

(4) Specifications of axle brake

The specifications of trailer axle braking are related to the rated load of the axle,

It usually have following specifications: 311x190mm, 381x220mm, 420x180mm, 420x200mm and 420x220mm.

(5) Wheel track

The wheel track is the distance between the centers of the two tires on the left and right sides of the axle. It is the core parameter of the axle. The wheel track of trailer axle usually has 1816mm, 1820mm, 1840mm, 1850mm, 1968mm, 2050mm, 2160mm, etc. And the wheel track can be adjusted according to the trailer design requirements.

(6) Distance of two brake chambers

 The center distance of the brake chambers is the distance between the centers of the two chamber brackets, which is determined by the length of the camshafts, usually 354mm, 370mm, 390mm, etc. while the wheel track is same. The external dimensions of the brake chamber and the installation requirements determine the minimum distance between the centers of the brake chambers 223mm, otherwise it will affect the installation of the brake chambers.






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