Classification and working principle of road milling machines

source：http://www.xrocktools.com/ Release Time：2015-09-11 15:13:22

Road milling machine is one of the main types of asphalt pavement maintenance construction machinery, mainly used for removing bumps, oil waves, mesh patterns, ruts, etc. from asphalt concrete surface layers such as highways and urban roads.

Using a road milling machine to mill damaged old pavement layers and then laying new ones is the most economical modern maintenance method. Due to its high work efficiency, simple construction process, easy control of milling depth, convenient and flexible operation, good maneuverability, and the ability to directly recycle milled old materials, it is widely used in urban municipal road and highway maintenance projects.

According to the milling form, milling machines can be divided into two types: cold milling and hot milling. The cold milling configuration has high power, fast tool wear, uniform cutting material particle size, and can be equipped with a sprinkler device for water spraying. It is widely used and has become a series of products; The hot milling type has a more complex structure due to the addition of a heating device, and is generally used for road surface regeneration operations.

According to the rotation direction of the milling rotor, it can be divided into two types: forward milling and reverse milling. If the rotation direction of the rotor is the same as the rotation direction of the wheels when the milling machine is moving, it is called forward milling; otherwise, it is called reverse milling.

According to the structural characteristics, it can be divided into two types: wheeled and tracked. Wheeled mobility is good and easy to transition, especially suitable for small and medium-sized road operations; Crawler type milling machines are mostly large milling machines with a milling width of over 2000mm.

Working principle explanation:

A general milling machine consists of an engine, frame, milling rotor, milling depth adjustment device, hydraulic components, aggregate conveying device, steering system, and braking system.

The milling rotor is the main working component of a milling machine, consisting of a milling rotor shaft, a tool holder, and a tool head. It directly contacts the road surface and works through its high-speed rotating milling cutter to achieve the purpose of milling. The milling machine is equipped with an automatic leveling device, which uses the milling rotor side cover as the milling reference surface to control two positioning hydraulic cylinders to maintain a constant milling depth;

Its hydraulic system is used to drive the rotation of milling rotors, the walking of the whole machine, and the operation of auxiliary devices. It is generally a closed hydraulic system with multiple independent pumps, which does not interfere with each other during operation and has high reliability;

Some milling machines are equipped with tilt adjusters as needed to control the tilt of the rotor; Generally, large milling machines have an aggregate conveying device consisting of a conveyor belt and a collector. It can concentrate the milled bulk materials and transport them to randomly moving transport vehicles. The height of the conveying arm can be adjusted and can swing left and right to adjust the discharge position.

When the specifications and models of milling machines are different, their structures and layouts may also differ slightly, but the basic working principles are the same or similar. The power transmission route of milling machine: engine → hydraulic pump → hydraulic motor, hydraulic cylinder → working device.

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