What are the differences between wheeled excavator chassis structure and crawler Komatsu track rollers PC2000-7

What are the differences between wheeled excavator chassis structure and crawler

Wheeled excavators are a common type of excavator. Compared with crawler excavators, they are more maneuverable and flexible, and are a good choice for urban construction. Compared with the latter, the main difference lies in the chassis form, so what is the chassis structure of wheeled excavators?

Wheeled excavators were born in Europe, and Europe is still the largest market and production base for wheeled excavators. As early as after World War II, before the birth of hydraulic excavators, wheeled excavators appeared in Europe, mainly used for operations on city streets. Naturally, a large number of technologies and ready-made parts from trucks were adopted, such as drive axles, steering drive axles, gearboxes, brake systems, etc., and 4X4 drive was usually adopted.China manufacturer offer excavator spare parts track roller construction machinery parts excavator bottom roller for PC2000-7

Mechanical wheel excavator, obviously using truck axles

When hydraulic excavators were first introduced, most manufacturers used wheeled chassis, and three-wheeled ones were more common. This is because the excavator needs to stably transfer the load to the ground when working, so elastic suspension devices cannot be used. If the four wheels are rigidly connected to the frame, they will not be able to touch the ground at the same time on uneven ground, making it difficult to support stably.China Supplier Assembly excavator track roller PC2000-7

Liebherr's early L-300 excavator used a 3-wheel chassis

Soon, the drive axle swing technology appeared, allowing a drive axle to swing horizontally at a certain angle, usually no more than 10 degrees, so that all four wheels can touch the ground on uneven ground, and the three-wheel form was soon eliminated. Since then, wheeled excavators and crawler excavators have been developing side by side.excavator bottom roller PC2000-7

A common frame type now, with a front shovel and rear outriggers

However, since wheeled excavators have to travel on roads, they must comply with relevant road regulations, including length, width, height, axle load, etc. This limits the tonnage of wheeled excavators. When crawler excavators continue to grow larger or smaller, wheeled excavators can only be controlled in the range of 10 to 25 tons, but this is enough to meet the needs of urban working conditions.

Front and rear axle structure, the rear axle is fixed on the frame, and the front axle can swing

Like crawler excavators, wheeled excavators also have a lower structure, which is also connected to the upper structure through a central slewing bearing, and obtains hydraulic power and control lines from the upper structure through a central slewing joint. Usually, wheeled excavators adopt a 4X4 drive form, and the front and rear drive axles are connected by a transmission shaft, and no inter-axle differential is used. Usually the front axle is a steering drive axle, which is also a swing axle, and the rear axle is usually fixedly connected to the frame.

The dozer blade has a similar function to the outriggers and can also level the ground

The drive axle is driven by a hydraulic motor, usually only one. To increase the torque, the gearbox is used to slow down the vehicle. 2-in-2-out is more common. The high gear is suitable for road conditions, generally not exceeding 40 km/h, and the low gear does not exceed 10 km/h and is used for movement during operations.

Outriggers for increased lateral stability

Early wheeled excavators usually did not have outriggers, which made the excavators unstable and limited their operating performance. The rear outriggers gradually became popular, improving the lateral stability and allowing the excavators to fully exert their performance. The most common types now are 4 outriggers and 2 outriggers + dozer.

Steering and braking usually use hydraulic cylinders to control the deflection of wheels and disc brake systems. Since the output of wheeled excavators is far less than that of crawler excavators, most manufacturers do not produce related parts by themselves. Gearboxes, axles, etc. are provided by supporting manufacturers, so steering and braking systems are actually solved by supporting manufacturers.

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